Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Hi, my name is Miss James and I can't wait to find out just how clever you are in our lesson today. For ...

A number line can be useful when answering questions involving negative numbers. When adding a positive number, go up the number line (move to the right). When subtracting a positive number, go down ...

Count back & use the relationship between addition and subtraction to subtract within 20. Warm up with a Mystery Math Mistake to find the error in DC's addition. Use ...

Here is a part-whole model. Sometimes the model is rotated. It looks different, but it still has two parts and a whole. We can use this model to help us solve problems. We can put 4 things in one of ...

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 ...