Question

write the missing digit to make the number divisable by three 3_,817

Answer 1

If a number is divisible by 3, its digits add up to a divisor of 3.
\[3+8+1+7 = 19\]
You will now notice that there is more than one answer. It could either be 2, 5, or 8 because
\[3+2+8+1+7 = 21\]\[21/3=7\]
\[3+5+8+1+7 = 24\]\[24/3=8\]
\[3+8+8+1+7 = 27\]\[27/3=9\]

Answer 2

thanks