Chapter 2 of 11All chapters
Chapter 2 of 11
Splitting numbers
Break one factor into friendly pieces.
The core move
Break one number into parts that are easy to multiply, then add the pieces. For 17 times 6, do 10 times 6 which is 60, then 7 times 6 which is 42, giving 102.
- This is the distributive law, the same thing long multiplication does on paper.
- Split into tens and units first. It works for almost every two digit problem.
Adding the same way
For 47 plus 38, add the tens to get 70, then the units to get 15, then combine for 85. Keeping the running total in tens is easier than tracking carries.