← Beads Before Numbers · Lesson 3 of 3
Handing on a ten
When a rod has no room for what you want to add, you hand a ten to the rod on the left and take the difference back from this one.
To add 9 to a rod showing 6: you cannot fit nine more. Add one bead on the tens rod (that is ten), then take one away here, because ten is one more than nine. The rod now shows 5, and the tens rod shows 1: fifteen.
This is the "carry" from school, done with your fingers: the pairs that make ten are the whole secret.
A rod shows 6 and you want to add 9, but there is no room. What do you do?
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