Add Three-Digit Numbers

Give students practice adding three-digit numbers within 1,000! This worksheet, designed for third- and fourth-graders, features 15 problems that require students to find the sum of two three-digit numbers. In each problem, the addends are stacked vertically to encourage students to use the standard algorithm. Most of the problems require regrouping. This worksheet is a great way for students to build fluency with addition and prepare to add numbers with more digits.