Fractions and Decimals - Solutions

 CBSE Class –VII Mathematics

NCERT Solutions
Chapter 2 Fractions and Decimals
 (Ex. 2.1)


Question 1. Solve:

(i)2-35          (ii) 4 + 78       (iii)35+27    (iv) 911415

(v)710+25+32    (vi)i223+312 

(vii)812358

Answer: (i) 235 = 1035=75 = 125

(ii)4+78 = 32+78=398 = 478

(iii)35+27 = 21+1035 = 3135

(iv)911415 = 13544165=91165

(v) 710+25+32 = 7+4+1510 = 2610=135 = 235

(vi) 223+312 = 83+72 = 16+216 = 376 = 616

(vii)812358 = 172298 = 68298 = 398 = 478

Question 2. Arrange the following in descending order:

(i) 29,23,821

(ii) 15,37,710

Answer: (i) 29,23,821  1463,4263,2463 [Converting into like fractions]

 4263>2463>1463 [Arranging in descending order]

Therefore, 23>821>29

(ii) 15,37,710 1470,3070,4970 [Converting into like fractions]

 4970>3070>1470 [Arranging in descending order]

Therefore, 710>37>15

Question 3. In a “magic square”, the sum of the numbers in each row, in each column and along the diagonals is the same. Is this a magic square?

411

911

211

311

511

711

811

111

611

(Along the first row 411+911+211=1511)

Answer: Sum of first row = 411+911+211=1511 [Given]

Sum of second row = 311+511+711=3+5+711=1511

Sum of third row = 811+111+611=8+1+611=1511

Sum of first column = 411+311+811=4+3+811=1511

Sum of second column = 911+511+111=9+5+111=1511

Sum of third column = 211+711+611=2+7+611=1511

Sum of first diagonal (left to right) = 411+511+611=4+5+611=1511

Sum of second diagonal (left to right) = 211+511+811=2+5+811=1511

Since, the sum of fractions in each row, in each column and along the diagonals are same, therefore, it s a magic square.

Question 4.  A rectangular sheet of paper is 1212 cm long and 1023 cm wide. Find its perimeter.

Answer: Given: The sheet of paper is in rectangular form.

Length of sheet = 1212 cm and Breadth of sheet = 1023 cm

Perimeter of rectangle = 2 (length + breadth)

2(1212+1023) = 2(252+323)

2(25×3+32×26) = 2(75+646)