Vertical Addition by Partition with 2-digit Numbers 12 + 71 80 (10 + 70) Add the tens 3 (2 + 1) Add the units 83 Vertical Addition by Partition with 3-digit Numbers 398 + 562 800 (300 + 500) Add the hundreds 150 (90 + 60) Add the tens 10 (8 + 2) Add the units 960 |