        CLASS 6      MATHS    CHAPER 2                   Whole Numbers

EXERCISE 2 D              {13/05/’21}                {ANSWERS} »

Q.1. C.W. (i). 57 × = 12 × 57                (Commutative Property)

(ii). 1623 × 1 = 1623                                      (Property of one)

(iii). 0 × 8135 = 0                                  (Property of Zero)

(iv). (17 × 24) × 102 = 17 × (24 × 102)         (Associative property)

(v). 87 × 19 = (80 × 19) + (7 × 19)       (Distributive Property

(vi). 10 × 100 × 0 = 0                            (Property of Zero)

(vii). 28 × 197 = 28 × 200 – 28 × 3      (Distributive property

of multiplication over subtraction)

(viii). 135 × 198 – 135 × 98 = 135 × 100 (Distributive property

of multiplication over subtraction)

(ix). 256 × 28 = 256 × 10 + 256 × 8 + 256 ×10   (Distributive property

Q.2. C.W. (i). 2 × 2056 × 50 = (2 × 50) × 2056

= 100 × 2056 = 205600

(ii). 25 × 766 × 4 = (25 × 4) × 766 = 100 × 766 = 76600

(iii). 8 × 1593 × 125 = (8 × 125) × 1593

= 1000 × 1593    = 1593000

(iv). 625 × 18 × 16 × 2 = (625 × 16) × (18 × 2)

= 10000 × 36     = 360000

Q.3.  C.W. (i). 435 × 17 + 435 × 3 = 435 × (17 + 3)

= 435 × 20 = 8700

H.W. (ii). 1723 × 86 + 1723 × 14 = 1723 × (86 + 14)

= 1723 × 100 = 172300

(iii). 7135 × 176 – 7135 × 76 = 7135 × (176 – 76)

= 7135 × 100 = 713500

(iv). 11934 × 27 + 11934 × 13 + 11934 × 60

= 11934 × (27 + 13 + 60)    = 11934 × 100   = 1193400

Q.4. C.W. (i). 938 × 104 = 938 × 100 + 938 × 4

= 93800 + 3752 = 97552

H.W. (ii). 325 × 1008 = 325 × (1000 + 8)

= 325 × 1000 + 325 × 8   = 325000 + 2600 = 327600

(iii). 998 × 534 = (1000 – 2) × 534 = 1000 × 534 – 2 × 534

= 534000 – 1068 = 532932

(iv). 1078 × 96 = 1078 × (100 – 4) = 1078 × 100 – 1078 × 4

= 107800 – 4312 = 103488

(v). 635 × 99 = 635 × (100 – 1) = 635 × 100 – 635 × 1

= 63500 – 635 = 62865

( vi). 2341 × 999 = 2341 × (1000 – 1)

= 2341 × 1000 – 2341 × 1     = 2341000 – 2341 = 2338659

Q. 5. C.W. The greatest three digit number = 999

The greatest four digit number = 9999

Required product = 999 × 9999 = 999 × (10000 – 1)

= 999 × 10000 – 999 × 1 = 9990000 – 999 = 9989001 Ans.

Q. 6. H.W. The amount of milk the vendor supplies to the

School in the morning = 42L

The amount of milk the vendor supplies to the school

In the evening = 58 L

Therefore the total amount of milk the vendor supplies

To the school = 42 L + 58 L = 100 L

The cost of milk per litre = 45

Using distributive property, we get

The cost of milk per day = 100 L × 45 = 100 × (40 + 5)

= 100 × 40 + 100 × 5 = 4000 + 500 = 4500 Ans.

Do by yourself the Multiple Choice Questions (MCQs)

************************************************

CLASS 6      MATHS    CHAPER 2                   Whole Numbers

EXERCISE 2 C              {10/05/’21}                {ANSWERS} »

Q. 1. C.W. (i). 456 – 215 = 241           check : 215 + 241 = 456

(ii). 15795 – 9784 = 6011                  check: 9784 + 6011 = 15795

H.W. (iii). 20000 – 9999 = 10001       check: 9999 + 10001 = 20000

Q.2. C.W. (i). 1340 - ________ = 990

Let the unknown number be x.

Then, 1340 – x = 990

» x + 990 = 1340         » x = 1340 – 990

= 350 Ans.   [1340 – 350 = 990]

(ii).5245 - ________  = 3198

Let the unknown number be x.

Then, 5245 – x = 3198

» x +3198 = 5245           » x = 5245 – 3198

= 2047 Ans.     {5245 – 2047 = 3198}

H.W. (iii). 10000 – ------------- = 7235

Let the number be x.

Then, 10000 – x = 7235

» x + 7235 = 10000           » x = 10000 – 7235

= 2765 Ans.              {10000 – 2765 = 7235}

Q.3. C.W. (i). n – 25 = 83           » n = 83 + 25 = 108 Ans.

(ii). N + 104 = 823             » n = 823 – 104 = 719 Ans.

Q.6. Amount Pankaj has in his bank account = 15,356

Amount he deposited more in a month = 4234

Total amount Pankaj has in his bank account at present =

15, 356 + 4234        = 19590

Amount he withdrew from his bank account = 2916

Therefore the amount in his account at the end of the month =

19, 590 – 2916         = 16674 Ans.

Do by Yourself Q.4 & Q.5 of the Multiple Choice Questions (MCQ)

****************************************************

CLASS 6      MATHS    CHAPER 2                   Whole Numbers

EXERCISE 2 B             {06/05/’21}                {ANSWERS} »

Q.1. C.W. Do write in Your Maths book itself.

(i). 639 +  256    = 256 + 639      commutative property

(ii). 384 + 0  =  0    + 384  =    384       Additive Property of Zero

(iii). ( 45 +   67  )  + 120 =   45  + ( 67 +  120 )      Associative property

Q.2. C.W. (i). 519 + 1275 = 1794; 1275 + 519 = 1794

Yes, both sums are equal. Commutative property

(ii). H.W. 1636 +492 = 2128; 492 + 1636 = 2128

Yes, both sums are equal. Commutative property

Q.3. C.W. (i). 426 + 315 + 474      » (426 + 474) + 315 » 900 + 315

= 1215 Ans.

H.W. (ii). 1538 + 322 + 462 + 578     » (1538 + 462) + (322 + 578)

» 2000 + 900   = 2900 Ans.

H.W. (iii). 22 + 86 + 97 + 11 + 14 + 78 + 89   » (22 + 78) + (86 + 14) + (11 + 89) + 97

» 100 + 100 + 100 + 97     = 397 Ans.

Q,4. Tick in your book itself.

Q.5. H.W. a + a = a » whole number ‘a’ = 0 Ans. (0 +0 = 0)

******************************************************

CLASS 6      MATHS    CHAPER 2                   Whole Numbers

EXERCISE 2 A             {03/05/’21}                {ANSWERS} »

Q.1. Do write in Your Maths book itself.

(i). 1       (ii). 0          (iii). natural        (iv). greater        (v). 1

Q. 2.The three consecutive successors of 10999 are 11000,

11001 & 11002.

Q.3. The three whole numbers just occurring before 20001

are 19998, 19999 & 20000.

Q.4. (i). 730, 703 < 730              (ii). 1753, 1753 > 1573

(iii). 48932, 48932 > 8945                   (iv). 1002345, 1002345 > 1000567

Q.5. Do write in your Maths book itself.

(i). T        (ii). F          (iii). T         (iv). F         (v). F

Do by yourself the Multiple Choice Questions (MCQs)

****************************************************

CLASS 6      MATHS    CHAPER 1                   NUMBERS

EXERCISE 1 G             {29/04/’21}                {ANSWERS} »

Q. 1. C.W.    Number of people voted in an hour = 90, 018

Number of hours = 12, Therefore the total number of people

voted in 12 hours = 12 × 90,018. An approximation for 12 × 90,018

is 12 × 90000 = 10, 80,000         (since one million = 10 lakh)

Yes, the newspaper gave a sensible account of the number

of votes cast in the election.

Q.2. [Tick in your Maths book. C.W.] (i). 4 × 52

» 52 to the nearest ten is 50. So, 4 × 50 = 200 Ans.

(ii). 8 × 31        »31 to the nearest ten is 30.

So, 8× 30 = 240 Ans.

(iii). 2 × 898    »898 to the nearest hundred is 900.

So, 2 × 900 = 1800 Ans.

(iv). 3 × 88       »88 to the nearest ten is 90.

So, 3 × 90 = 270 Ans.

(v). 4 × 92        »92 to the nearest ten is 90.

So, 4 × 90 = 360 Ans.

(vi). 3 × 296    » 296 to the nearest hundred is 300.

So, 3 × 300 = 900 Ans.

Q. 3. C.W. (i). 48 × 7         » 48 to the nearest ten is 50.

So, 50 × 7 = 350 Ans.        » The product of 48 × 7 = 336.

(ii). 65 × 57     » 65 to the nearest ten is 70 and

57 to the nearest ten is 60. So, an approximation for

65 × 57 is 70 × 60 = 4200 Ans .The product of 65 × 57 = 3705.

(iii). 325 × 6    » 325 to the nearest hundred is 300.

So, 300 × 6 = 1800 Ans. The product of 325 × 6 = 1950.

(iv). 65 × 21    » 65 to the nearest ten is 70 and

21 to the nearest ten is 20.So an approximation for

65 × 21 is 70 × 20 = 1400 Ans. The product of 65 × 21 = 1365.

H.W. (v). 58 × 83     » 58 to the nearest ten is 60 and 83 to

the nearest ten is 80.So an approximation for 58 × 83 is

60 × 80 = 4,800 Ans. The product of 58 × 83 = 4,814.

(vi). 434 × 87  » 434 to the nearest hundred is 400 and

87 to the nearest ten is 90.So an approximation for 434 × 87

is 400 × 90 = 36,000 Ans. The product of 434 × 87 = 37,758.

(vii). 702 × 65 » 702 to the nearest hundred is 700 and

65 to the nearest ten is 70.So an approximation for 702 × 65

is 700 × 70 = 49,000 Ans. The product of 702 × 65 = 45,630.

(viii). 815 × 477        » 815 to the nearest hundred is 800 and

477 to the nearest hundred is 500.So, an approximation for

815 × 477 is 800 × 500 = 4, 00,000 Ans. The product of 815 × 477

= 3, 88,755. Thus, the answer is sensible.

Q.4. Write in your Maths book.  C.W.                  (03/05/’21)

(i). 80 Ans.      (ii). 30 Ans.         (iii). 10 Ans.        (iv). 20 Ans.

(v). 30 Ans.     (vi). 30 Ans.

Q.5. C.W. (i). Ans. The estimated value of 563 ÷ 8 is 560 ÷ 8 = 70 Ans.

[563 to the nearest ten is 560] The quotient of 563 ÷ 8 is 70.375.

[70.375 round off to whole number is 70] Thus, the answer is sensible.

(ii). C.W. Ans. The estimated value of 714 ÷ 7 is 700 ÷ 7 = 100 Ans.

The quotient of 714 ÷ 7 is 102. Thus, the answer is sensible.

[102 round off to whole number is 100]

(iii). C.W. Ans. The estimated value of 7187 ÷ 9 is 7200 ÷ 9 = 800 Ans.

The quotient of 7187 ÷ 9 is 798.556. Thus, the answer is sensible.

(iv). H.W. Ans. The estimated value of 2657 ÷ 4 is 2700 ÷ 4 = 675

675 round off to nearest hundred is 700 Ans.

The quotient of 2657 ÷ 4 is 664.25.Thus, the answer is sensible.

(v). H.W. Ans. The estimated value of 4423 ÷ 21 is 4400 ÷ 21 = 209.5

The quotient of 4423 ÷ 21 is 210.6. 209.5 round off to the nearest

whole number is 210 Ans. Thus, the answer is sensible.

(vi). H.W. Ans. The estimated value of 3758 ÷ 97 is 3800 ÷ 100 = 38

38 round off to nearest ten is 40 Ans. The quotient of 3758 ÷ 97 = 38.7

(vii). H.W. Ans. The estimated value of 5294 ÷ 128 is 5300 ÷ 130 = 40.8

40.8 round off to nearest ten is 40 Ans. The quotient of 5294 ÷ 128 = 41

(viii). H.W. Ans. The estimated value of 7982 ÷ 789 is 8000 ÷ 800 = 10 Ans.

[7980 ÷ 790 = 10.1 = 10].  The quotient of 7982 ÷ 789 = 10.1.

Do LEARN from page no.32 and 33. Do WRITE in your MATHS book or MATHS

Rough copy REVISION EXERCISE AND Challenge! From page no. 33 and 34.

*************************************************************

CLASS 6      MATHS    CHAPER 1                   NUMBERS

EXERCISE 1 E             {29/04/’21}                {ANSWERS} »

Q.1. C.W. (i). 51 + 47   » Both the numbers have place

values of tens, so we round off to the nearest ten.

51 is rounded down to 50, 47 is rounded up to 50.

Thus, estimated sum = 50 + 50 = 100 Ans.

(ii). 528 + 62     » The smaller number 62 has place

values of tens, so we round off to the nearest ten.

528 is rounded up to 530, 62 is rounded down to 60.

Thus, estimated sum = 530 + 60 = 590 Ans.

(iii). 2314 + 372       » The smaller number 372 has place

values up to hundreds, so we round off to the nearest

hundreds.

2314 is rounded down to 2300, 372 is rounded up to 400.

Thus, estimated sum = 2300 + 400 = 2700 Ans.

H.W. (iv). 1521 + 6325     » Both the numbers have place

values up to thousands, so we round off to the nearest

thousand.

1521 is rounded up to 2000, 6325 is rounded down to 6000.

Thus, estimated sum = 2000 + 6000 = 8000 Ans.

(v). 43278 + 2902    » The smaller number has place

Values up to thousands, so we round off to the nearest

thousand.

43278 is rounded down to 43000, 2902 is rounded up to

3000. Thus, estimated sum = 43000 + 3000 = 46000 Ans.

(vi). 7893 – 4164               » Both the numbers have place

values  up to thousands, so we round off to the nearest

thousand.

7893 is round up to 8000, 4164 is round down to 4000.

Thus, estimated difference = 8000 – 4000 = 4000 Ans.

(vii). 47348 – 2267            » The smaller number 2267 has

place values up to thousands, so we round off to the

nearest thousand.

47348 is rounded down to 47000, 2267 is rounded down

to 2000. Thus, estimated difference = 47000 – 2000

= 45000 Ans.

(viii). 2597 – 390               » The smaller number 390 has

Place values up to hundreds, so we round off to the

nearest hundred.

2597 is rounded up to 2600, 390 is rounded up to 400.

Thus, estimated difference = 2600 – 400 = 2200 Ans.

(ix). 9001 – 557                 » The smaller number 557

has place values up to hundreds, so we round off to

the nearest hundred.

9001 is round down to 9000, 557 is round up to 600.

Thus, estimated difference = 9000 – 600 = 8400 Ans.

(x). 65662 – 4465              » The smaller number 4465

has the place values up to thousand, so we round off

to the nearest thousand.

65662 is round up to 66000, 4465 is round down to 4000.

Thus, estimated difference = 66000 – 4000 = 62000 Ans.

(i). 5085    (ii). 3927  (iii). 6024      (iv). 1966      CLASS 6      MATHS    CHAPER 1   NUMBERS       EXERCISE 1 C   {12/04/’21}

Q.1. C.W.

(i) 53, 673 – Fifty three thousand six hundred seventy three.

(ii) 430, 057 – Four hundred thirty thousand fifty seven.

(iii) 78, 823, 761 – Seventy eight million eight hundred twenty three thousand seven hundred sixty one.

(iv) 600, 003 – Six hundred thousand three

(v) 1, 369, 864, 005 – One billion three hundred sixty nine million eight hundred sixty four thousand five

(vi) 80, 112, 005, 459 – Eighty billion  one hundred twelve million five thousand

Four hundred fifty – nine

Q.2. C.W.     (i)  606, 712           (ii) 4, 813, 300              (iii) 809, 008, 007

(iv) 3, 018, 901,017     (v) 16, 519, 913,702             (vi) 38, 000, 500, 048

Q.3. H.W.            8, 050, 099 – Eight million fifty thousand ninety – nine.

Q.4. H.W.            728, 998 ; 728, 999 ; 729, 000

Q.5. H.W.          (i) 9, 99, 99, 876   -      Nine crore ninety nine lakh ninety nine   thousand eight hundred seventy – six

(ii) 99, 999, 876 – Ninety nine million, nine hundred ninety nine thousand eight hundred seventy six.

Q.6. H.W. wirte  in your Book.

(i) Three hundred thousand – Three lakh

(ii) Three billion – Three hundred crore

(iii) Thirty million – Three crore

(iv) Three million – Thirty lakh

Do by yourself the Multiple Choice Questions (MCQs) in your

Maths rough Copy.

CLASS 6      MATHS    CHAPER 1   NUMBERS       EXERCISE 1 B   {12/04/’21}

Q.1. C.W.

(i) 6, 80, 483 – Six lakh eighty thousand four hundred eighty three.

(ii) 12, 36, 748 – Twelve lakh thirty six thousand seven hundred forty eight.

(iii) 8, 30, 09, 007 – Eight crore thirty lakh nine thousand seven.

(iv) 10, 00, 30, 004 – Ten crore thirty thousand four.

(v) 33, 04, 05, 078 – Thirty three crore four lakh five thousand seventy eight.

Q.2. C.W.

(i) 5, 03,785           (ii) 80, 15, 205             (iii) 90, 07, 09, 403

(iv) 1, 01, 01, 001             (v) 270, 88, 65, 295

Q.3. C.W.

(i) 80,000      (ii) 8, 00, 000          (iii) 80, 00, 000                 (iv) 8, 00, 00, 000

Q.4. C.W.

(i) 80, 000 + 3, 000 + 500 + 90 + 6

(ii) 70, 00, 000 + 5, 00, 000 + 10, 000 + 6, 000 + 900 + 30

(iii) 40,00,00,000+2,00,00,000+60,00,000+5,00,000+90,000+3,000+200+40

Q.5. C.W.

(i) 5, 07, 816                    (ii) 79, 00, 628             (iii) 24, 00, 70, 605

Q.6. C.W. write in your BOOK.

(i) 19, 25, 875 < 19, 52, 875              (ii) 60, 12, 40, 627 < 61, 02, 04, 726

Q.7. H.W.      Numbers in largest to smallest

(i) 9, 07, 652;      8, 95, 072;      6, 90, 672;       6, 09, 762

(ii) 9, 01, 83, 726;    9, 00, 25, 900;     8, 93, 45, 015;     8, 45, 39, 150

Q.8. H.W.      Numbers in smallest to largest

(i) 4, 60, 570;    5, 72, 803;     6, 81, 906;    7, 90, 856

(ii) 9, 53, 654;    2, 09, 62, 000;    11, 00, 83, 000;     64, 15, 23, 453

Q.9. H.W.

(i) 9, 99, 99, 987                       (ii) 1, 00, 002

Q.10. H.W.

(i) The smallest seven digit number = 10, 00, 000

The largest seven digit number = 99, 99, 999

Therefore total number of seven digit numbers = 99, 99, 999 – 10, 00, 000 + 1

= 90, 00, 000 Ans.

(ii) The smallest nine digit number = 10, 00, 00, 000

The largest nine digit number = 99, 99, 99, 999

Therefore total number of nine digit numbers = 99, 99, 99, 999 – 10, 00, 00, 000 + 1

= 90, 00, 00, 000 Ans.

Do by yourself the Multiple Choice Questions (MCQs) and Challenge in your

Maths rough Copy.  