The common-core math standards require that students learn the standard algorithm for multi-digit adding and subtracting—you know, the process in which you line the numbers up vertically to add or ...

When you subtract using large numbers, it's often better to use a written method. Column subtraction is a good written method to take one number away from another. It involves writing the smaller ...

Subtraction from a two-digit number Two cartoon characters use labelled balloons to show subtractions of 10 from several two-digit numbers of less than 100. One character thinks of a number and the ...