Question

Spiral Review7 Mrs. Dinson has 9 pencils on her desk. She has3 pencils in a box. To find the number of pencilsshe has altogether, Mrs. Dinson writes. 9 + 3 = 12.What other addition fact could Mrs. Dinson use?

Answer 1

As a sum of two numbers we could use the property that says that the order of the terms does not change the result.

Then, if we add 9 and 3 as 9 + 3 = 12, because she has 9 pencils on her desk and 3 pencils in a box, we can also use the addition fact 3 + 9 = 12, knowing that she has 3 pencils in a box and 9 pencils on her desk.

We just have changed the order of the addition terms without changing the result, which is always 12 for an addition of 3 and 9.

Answer: 3 + 9 = 12