some questions of playing with numbers
Answers
Answer:
Question 1.
Write the following numbers in generalised form.
(a) ab
(b) 85
(c) 132
(d) 1000
Solution:
(a) ab = 10 × a + 1 × b = 10a + b
(b) 85 = 10 × 8 + 1 × 5 = 10 × 8 + 5
(c) 132 = 100 × 1 + 10 × 3 + 1 × 2 = 100 × 1 + 10 × 3 + 2
(d) 1000 = 1000 × 1
Question 2.
Write the following in usual form.
(a) 3 × 100 + 0 × 10 + 6
(b) 5 × 1000 + 3 × 100 + 2 × 10 + 1
Solution:
(a) 3 × 100 + 0 × 10 + 6 = 300 + 0 + 6 = 306
(b) 5 × 1000 + 3 × 100 + 2 × 10 + 1 = 5000 + 300 + 20 + 1 = 5321
1. If 42x5 is a multiple of 9 and x is a digit, then find the value of x.
2. Is 10011 divisibly by 3?
3. If 3x12 is a multiple of 3 and x is digit, then find the value of x.
4. If 35x is a multiple of 9 and x is digit, then find the value of x.
5. The usual form of the number 9 × 100 + 7 × 1
(a) 97
(b) 9007
(c) 907
(d) 16