Page 48 - MathGPT_V1.0_C5

D:\Surender Prajapati\Books Final_CBSE and ICSE\ICSE\Preparatory_Stage_Maths-5_(31-10-2023)\Open_Files\CHAP_02
\\November 3, 2023 10:57 AM Surender Prajapati Proof 5 Reader _________________________ Date: ___________________74

Example: Estimate the answer of each of the following.

(a) 2,960 + 1,730 (b) 9,300 – 6,420 (c) 4,465 × 8 (d) 24,581 ÷ 47
Solution:

(a) rounded to Estimated sum Actual sum
2960 3000
nearest 1000 3 0 0 0 2 9 6 0
rounded to + 2 0 0 0 + 1 7 3 0
1730 nearest 1000 2000 5 0 0 0 4 6 9 0

The estimated sum is close to the actual sum.

(b) rounded to Estimated difference Actual difference
9300 nearest 1000 9000 9 0 0 0 8 12 10

rounded to – 6 0 0 0 9 3 0 0
6420 nearest 1000 6000 3 0 0 0 – 6 4 2 0
2 8 8 0

The estimated difference is close to the actual difference.

(c) rounded to
4465 nearest 1000 4000 Estimated product Actual product

rounded to × 4 0 0 0 × 4 4 6 5
8
1 0
8 nearest 10 10 4 0 0 0 0 3 5 7 2 0

The estimated product is close to the actual product.

(d) Estimated quotient Actual quotient

24581 25000 (Rounding off to the nearest thousand) 5 2 3
2 4 5 8 1
47 50 (Rounding off to the nearest ten) 47 2 3 5
25,000 ÷ 50 = 500 1 0 8
9 4
1 4 1
1 4 1

The estimated quotient is close to the actual quotient. 0

Think and Answer
Ask your parent’s monthly income in total and estimate their yearly income. What
is the difference between their actual and estimated yearly income?

Practice Time 2E

1. Estimate the value of:

(a) 31,972 + 10,322 (b) 2,575 × 124 (c) 7,21,994 – 66,159 (d) 2,56,311 ÷ 578

46 Mathematics-5