Mathematics
Answer
(i) In the first factor tree, 90 = 10 × 9.
10 = 2 × ?, so the missing number is 5 (since 10 = 2 × 5).
9 = ? × 3, so the missing number is 3 (since 9 = 3 × 3).
(ii) In the second factor tree, 90 = 45 × ?, so the missing number is 2 (since 90 = 45 × 2).
45 = 15 × ?, so the missing number is 3 (since 45 = 15 × 3).
15 = ? × ?, so the missing numbers are 3 and 5 (since 15 = 3 × 5).
Related Questions
A number is divisible by both 3 and 8. By which other numbers will that number be always divisible?
State whether the following statements are true (T) or false (F):
(i) If a number is divisible by 4, it must be divisible by 8.
(ii) If a number is divisible by 3, it must be divisible by 9.
(iii) If a number is divisible by 9, it must be divisible by 3.
(iv) If a number is divisible by 9 and 10 both, it must be divisible by 90.
(v) If a number divides the sum of two numbers, then it must divide the two numbers separately.
(vi) If a number is divisible by 3 and 8 both, it must be divisible by 12.
(vii) If a number is divisible by 6 and 15 both, it must be divisible by 90.
Find the prime factorisation of the following numbers:
(i) 72
(ii) 172
(iii) 450
(iv) 980
(v) 8712
(vi) 13500
Write the smallest and the greatest 3-digit numbers and express them as the product of prime.