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 ...

Join Mrs. McCartney for an addition number talk with D.C.! Join Mrs. McCartney for an addition number talk with D.C.! Get ready to have some fun subtracting two-digit numbers with regrouping and ...

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 ...

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 ...