As students add multi-digit numbers, they often find the need to regroup numbers. They regroup 1 ten into 10 ones, 1 hundred into 10 tens, and so on. Help your students practice this concept and develop conceptual and strategic knowledge with add two 4-digit numbers with regrouping worksheet. In each problem, the numbers are laid out in the horizontal format. Students should try to use different strategies involving composing and decomposing numbers to solve these problems. This will help them develop flexibility and fluency.