# Addition and subtraction

Contents

Learn how to add and subtract three-digit numbers by thinking about ones, tens, and hundreds.

Learn how to add numbers like 259 + 363. These addition problems are a harder than the ones we've done before because they require regrouping (also called carrying).

Learn how to subtract numbers like 363 - 259. These subtraction problems are a harder than the ones we've done before because they require regrouping (also called borrowing).

Learn strategies for solving addition problems within 1000.

Learn how to solve problems like "___ - 237 = 448" where you don't know one of the values in an addition or subtraction equation.