To add -4 and 5, draw the starting number on a number line and count to the right when adding numbers. What is the difference in temperature between a desert at 40 °C and a mountain top at -2 °C? \(40 ...

Students put all of their addition and subtraction skills together to solve equations. In this lesson, students put all of their addition and subtraction skills together to solve equations. Julia ...

Relating addition and subtraction and playing the game BUMP; counting down. Relating addition and subtraction and playing the game BUMP; Working with numbers, starting with a number and counting down ...

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 ...

Jackson Ryan was CNET's science editor, and a multiple award-winning one at that. Earlier, he'd been a scientist, but he realized he wasn't very happy sitting at a lab bench all day. Science writing, ...