Areteem: NT III Chapter 2

Online Course Discussion Forum

Hello!

I am stuck on 2.22, 2.25, 2.26, 2.30, and 2.32.

Did I do any calculation error for problem 2.25? Each column represents each type of coin and one "tally mark" represents one number of that coin.

Thanks!

Tina Jin

2.25: pay attention to pennies and dimes. When you get to "2" and "4", it is incorrect. Think about their parities (even or odd).

2.26: The operations won't change the total sum mod 3.

2.22: Each digit appear in each place the same number of times, except when 0 is the leading digit.

2.30: Similar to 2.26, consider mod 3.

2.32: for any two integers, their sum and difference have the same parity.