Page 42 - Math Skill - 4

40 Maths

Estimation of Products
To find out the estimation of product of two or more numbers, we round off the given numbers
and then calculate the product. Let us learn through examples.

Let’s Attempt

Example 1: Estimate the product of 23 and 65 to the nearest ten.
Solution: 23 rounded off to nearest ten = 20

65 rounded off to nearest ten = 70

Thus, estimated product = 20 × 70 = 1400
Example 2: Estimate the product of 287 and 219 to the nearest hundred.

Solution: 287 rounded off to nearest hundred = 300

219 rounded off to nearest hundred = 200
Thus, estimated product = 300 × 200 = 60000

Exercise 3.3

1. Estimate each of the following by rounding off to the nearest ten.
(a) 38 × 52 (b) 63 × 77 (c) 47 × 83

2. Estimate each of the following by rounding off to the nearest hundred.
(a) 273 × 106 (b) 608 × 291 (c) 294 × 186

Division

‘‘Division means equal sharing or equal grouping’’
As we know, division is repeated subtraction. For every division fact there is corresponding
multiplication fact. For example, 84 ÷ 4 = 21, the corresponding multiplication fact is 21 × 4 = 84.
Basically, division is an inverse process of multiplication.

Dividend = Divisor × Quotient + Remainder

For example, when we divide 238 by 6, we have
Dividend = 238, Divisor = 6 3 9
Quotient = 39 and Remainder = 4 6 2 3 8

Divisor × Quotient + Remainder = 6 × 39 + 4 = 234 + 4 = 238 – 1 8
5 8
Dividend = 238 – 5 4
Hence, Dividend = Divisor × Quotient + Remainder 4
For the division of large number, we use the method of long division.