Addition of 4 digit numbers, with and without regrouping. Here is the finest way to teach it: Partial sums are intuitive, much related to our mental processes, and it assigns every digit its real value to help your pupils building a solid number sense and develop sharp mental skills. 18 worksheets are included, featuring 3 differentiation levels. Additionally, each page targets a specific adding strategy: Adding 0 and 1.Making 10.Doubles.Near-doubles.Bridge to 10.Mix of all strategies.Try it o