Page 63 - Maths Skill - 6

Number Play 61

Let’s Attempt

Estimate 92 × 578

The first number, 92, can be rounded off to the nearest ten as 90.
The second number, 578, can be rounded off to the nearest hundred as 600.

Hence, the estimated product = 90 × 600 = 54,000.

Exercise 4.2

1. What is the largest 6-digit number whose digit sum is 17?
2. What is the smallest 5-digit number whose digit sum is 8?

3. What is the largest 2-digit number whose digit sum is 16?
4. What is the smallest 3-digit number whose digit sum is 13?

5. What is the largest 4-digit number whose digit sum is 19?
6. Estimate the product (note: multiplicands should be round off according to their value)

(a) 8 × 86 = __________ (b) 126 × 978 = __________

(c) 1012 × 846 = __________ (d) 1876 × 7495 = __________

(e) 96 × 856 = __________ (f) 199 × 294 = __________

ASSESSMENT TIME

COMPETENCY BASED QUESTIONS 4. Estimate the product 82 × 126
(i) 9000 (ii) 10000
A. Multiple-Choice Questions
1. What is the largest 5-digit number whose digit (iii) 8000 (iv) 10332
sum is 16? B. Fill in the Blanks
(i) 88000 (ii) 97000
(iii) 79000 (iv) 14700 1. The number read the same from left to right
and from right to left such a number are
2. What is the smallest 3-digit number whose digit called __________.
sum is 11?

(i) 560 (ii) 137 (iii) 128 (iv) 119 2. Which number is called ‘Kaprekar constant
_________.
3. What is the smallest 4-digit number whose digit
sum is 13? 3. The smallest 2-digit number whose digit sum
(i) 1237 (ii) 1532 is 11 _____________.
(iii) 1532 (iv) 4501