Remember : There are eight unique groups of three numbers that sum to 10, for example 1 + 2 + 7 = 10.
Task:Find the other seven groups of three numbers summing to 10 as one example given for you?
2 + 3 + 5 = 10
By the deficiency method or completing the whole method
7,8,9 close to 10
17,18,19, are close to 20
27, 28, 29, are close to 30
…………… and so on.
We can use this closeness for addition.