PLEASE, ANYBODY!

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N=1991*1993*1995*1997*1999 What is the sum of the hundreds, tens and units digits of N?

Find the smallest positive multiple of 21 that has no digit larger than 1.

What is the smallest positive integer n such that the rightmost three digits of n! and (n+1)! are the same?

Guest Oct 17, 2020

edited by Guest Oct 17, 2020

Guest · Answer 1 · 2020-10-17T04:14:07

1 - Why don't you just multiply them:1991*1993*1995*1997*1999=3160183 6203377055. Sum=0+5+5=10

2 - The smallest multiple of 21 with no digits > 1 =101,010

3 - The smallest n =10! =3,628,800 and 10+1 =11! =39,916,800