When multiplied out, what is the sum of the digits in the number $7^2 2^{2017} 5^{2018}$. I’m guessing there’s some trick to solve this problem, but I don’t know what it is. Thanks!
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Welcome to Mathematics Stack Exchange. Here is a MathJax tutorial – J. W. Tanner Oct 26 '20 at 01:47
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As for the sum of digits: My hint would be "compute modulo 10". – Johannes Kloos Oct 26 '20 at 12:28
