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 ...

How to subtract tens from two-digit numbers Bill and Bernie use labelled balloons to show subtractions of 10 from several two-digit numbers which are less than 100. Bernie thinks of a number and Bill ...

Your child continues to use tape diagrams as a visual tool to solve word problems. Your child continues to use tape diagrams as a visual tool to solve word problems. Now, he solves for an unknown in ...

Subtraction is taking away one number from another. Lilly has 4 balloons, but then one flys away. How many does she have left? You can use subtraction to find the answer. First there were 4 balloons.

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 ...

The National Council of Teachers of Mathematics is a public voice of mathematics education, providing vision, leadership, and professional development to support teachers in ensuring mathematics ...