Multiple choice general knowledge Last Digit of 9999 x 999999 9 7 1 6 Reveal answer Fill a bubble to check yourself C Correct answer Explanation To find the last digit of a product, multiply only the last digits: 9 x 9 = 81. The last digit is 1. Option C is correct. Any two numbers ending in 9 multiply to give a last digit of 1 (since 9 x 9 = 81).