Addition is finding the total of two or more numbers. You use the addition sign (+) when you want to add one number to another. Addition calculations also use the equals sign (=). The left side and ...

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 ...

When you are solving an addition calculation with a two-digit number, you need to think about tens and ones. A place value chart can help you to see the value of each digit in a number. For example, ...