Sometimes the calculation goes past a ten.
Then you split the task into two steps:
Step 1: First count up to the next ten.
Step 2: Then add on the rest.
Example: 8 + 5
8 + 2 = 10 (first up to 10)
10 + 3 = 13 (then add the rest)
The numbers filled in show the solution.
Example
8 + 5 = 8 + 2 + 3 = 10 + 3 = 13
For parents
What does this exercise practice?
This exercise teaches how to split numbers cleverly to add across the ten, one of the most important basic techniques for mental math up to 100.
Common pitfalls
Many children try to solve the task directly, without the step across the ten. That leads to mistakes. It helps to say the split out loud: how much is still missing up to the next ten?
How to practice at home
Calculate together while shopping: we have 8 apples, we need 13, how many are still missing? Use the ten as a stopping point.
Related: Calculation, Semi-written