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 4-digit and 3-digit numbers with regrouping worksheet. In each problem, the numbers are laid out in the vertical format. In this format, pair of digits in each successive place are tackled one by one. This helps students follow a structured approach.