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 ...

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 ...

Explains the concept of zero in mathematics, emphasizing its role as a number that represents the empty set. It illustrates how zero is used in addition and subtraction, showing that adding or ...

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 ...

In fourth grade, students focus most on using all four operations - addition, subtraction, multiplication, and division - to solve multi-step word problems involving multi-digit numbers. Fourth-grade ...

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, ...

Take this quiz to see how much you know about this topic already, then work through the guide and see if you can beat your score. Take a look at this number line. It shows 14 - 5 = 9. You can count ...