2022 AMC 8 Problems/Problem 17
Contents
Problem
If is an even positive integer, the notation represents the product of all the even integers from to . For example, . What is the units digit of the following sum?
Solution
Notice that once the units digit of will be because there will be a factor of Thus, we only need to calculate the units digit of We only care about units digits, so we have which has the same units digit as The answer is
~wamofan
Video Solution by OmegaLearn
https://youtu.be/wp9tOyJ3YQY?t=146
~ pi_is_3.14
Video Solution
https://youtu.be/Ij9pAy6tQSg?t=1461
~Interstigation
https://www.youtube.com/watch?v=FTVLuv_n9bY
~Ismail.Maths
Video Solution
https://youtu.be/hs6y4PWnoWg?t=80
~STEMbreezy
Video Solution
~savannahsolver
Video Solution (CREATIVE THINKING!!!)
~Education, the Study of Everything
See Also
2022 AMC 8 (Problems • Answer Key • Resources) | ||
Preceded by Problem 16 |
Followed by Problem 18 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | ||
All AJHSME/AMC 8 Problems and Solutions |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.