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 ...

You can add or subtract numbers in lots of different ways. You can use number lines, number bonds, fact families, 10 squares and counters, or even just writing the numbers down. Sometimes it is faster ...

The present paper describes the success, the methods (mental, informal written, standard algorithm) and the strategies of informal written arithmetic to be observed when 300 elementary students worked ...