Question

Write the smallest digit and the greatest digit in the blank space of each of the following numbers so that the number formed is divisible by 3 :
1.  __ 6724
2.  4765 __ 2

Answer 1

(a) We know that a number is divisible by 3 if the sum of all digits is divisible by 3.
Therefore,
Smallest digit : 2 → 26724 = 2 + 6 + 7 + 2 + 4 = 21
Largest digit : 8 → 86724 = 8 + 6 + 7 + 2 + 4 = 27

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(b) We know that a number is divisible by 3 if the sum of all digits is divisible by 3.
Therefore,
Smallest digit : 0 → 476502 = 4 + 7 + 6 + 5 + 0 + 2 = 24
Largest digit : 9 → 476592 = 4 + 7 + 6 + 5 + 0 + 2 = 33