You can find the difference between two numbers in more than one way. You can count up from the smaller number to the larger number. Or, you can count back from the larger number to the smaller number ...

Subtracting larger numbers in your head is not always easy, so you can use the column method to take one number away from another. You write the larger number above the smaller number, so that the ...

Common-core math aims to have students do less memorizing—but it’s being misinterpreted to have students do more, argues Kathy Liu Sun, an assistant professor of math education at Santa Clara ...