The digit in unit's place of the product 81 × 82 × 83 × ..... × 89 is :
A. 0
B. 2
C. 6
D. 8
Answer: Option A
Solution (By Examveda Team)
81 × 82 × 83 ×..... × 89 take unit digit multiply1 × 2 × 3 × 4 × 5 × 6 × 7 × 8 × 9 = 0
Since there is 5 and 2 are present
So we get 5 × 2 = 10 and the last digit of 10 is 0, so the last digit of the above number is also 0

Why 5*2 is multiplied