Editorial desk · Practical notes

Break an addition into friendly parts

Try 48 + 27. One method is to add 20 to 48, giving 68, then add the remaining 7 to get 75. Another is to move 2 from 27 to 48: 50 + 25 also gives 75.

Write both methods side by side. Notice that the second method changes the two parts but preserves their total. Explain that step in your own words before trying a new example.

Practice with 39 + 16 and check the result using a written calculation. The aim is not to race. It is to recognize a useful structure and know why it works.