Page 43 - Maths Class 05

g. 5 × (2 + 3) = 5 × 2 + 5 × 3 h. 9 + (1 + 18) = (9 + 1) + 18

Properties : Properties :

2. Fill in the blanks using the properties of subtraction.

a. 349 – _____ = 0 b. 798 – 798 = _____ c. 5179 – _____ = 5179
d. 1835 – 0 = _____ e. _____ – 1234 = 0 f. _____ – 5712 = 0

3. Fill in the blanks.
a. 134 × _________ = 245 × 134 b. 6213 × 270 = _________ × 6213

c. 519 × _________ = 3105 × 519 d. 8175 × _________ = 0
e. _________ × 8367 = 8367 f. _________ × 93653 = 0

Carry On

1. Multiply three thousand two hundred by twenty.

2. Divide the successor of 6499 by 13.

3. Multiply eighty thousand by nine hundred.
4. The remainder in 367 ÷ 6 is _______________ .

5. The quotient in 60 ÷ 7 is __________________ .
6. What number when multiplied by the successor of 69 gives 2100 ?

Estimation in Operations on Numbers

In the previous section, we have learnt to round off the numbers. Rounding off
numbers helps us to get the required information which is an approximation. In our

daily life, in many situations, we need not to use the exact numbers but estimate the
numbers to get close enough result.

Let us consider some examples to see estimation.
Estimating Sums

Example : Estimate the following sums to the nearest ten.

a. 53 + 39 b. 45 + 33

Solution :

a. Actual Sum Estimated Sum b. Actual Sum Estimated Sum
Rounding Rounding
5 3 off to the 5 0 4 5 off to the 5 0
Nearest Nearest
+ 3 9 + 4 0 + 3 3 + 3 0
10 10
9 2 Nearest 9 0 7 8 Nearest 8 0

10 10

Mathematics-5 43