Fill in the blanks and answer the questions about the colored cards.

Here are the answers for the blank spaces and the "Coloured cards" section.

1. What will you put in the place of the orange?

e)

$$2 + \boxed{7} = 7 + 2$$ $$9 = 9$$

The orange is $\boxed{7}$.

f)

$$8 + 1 = 1 + \boxed{8}$$ $$9 = 9$$

The orange is $\boxed{8}$.

g)

$$6 + \boxed{3} = 3 + 6$$ $$9 = 9$$

The orange is $\boxed{3}$.

h)

$$9 + 0 = \boxed{0} + 9$$ $$9 = 9$$

The orange is $\boxed{0}$.

i)

$$7 + \boxed{1} = 1 + 7$$ $$8 = 8$$

The orange is $\boxed{1}$.

j)

$$\boxed{1} + 6 = 6 + 1$$ $$7 = 7$$

The orange is $\boxed{1}$.

2. Coloured cards. Look at the cards. What do you notice?

You can notice that some different addition problems result in the same sum. For example, $4+5$, $8+1$, and $7+2$ all equal 9. You can also notice that changing the order of the numbers being added does not change the sum (this is called the commutative property of addition).