You can add or subtract numbers in lots of different ways. You can use number lines, number bonds, fact families, 10 squares and counters, or even just writing the numbers down. Sometimes it is faster ...

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 ...

Match fun story problems with the correct addition or subtraction expression. Join Mrs. Gray for number talk with the Counting Buddy Junior. Then get ready to match fun story problems with the correct ...

Test your understanding of place value with three-digit numbers. Start with a three-digit whole number such as 507. A spinner provides a randomly generated digit. Choose its place value and add it to ...

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, ...

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, ...