This is a problem of fact families, but <em>what is fact families?</em> Well it is a family of four things. Two of them are additions and two of them are subtractions. So this question asks about fact families by w<span>riting the <em>subtraction fact two ways</em>. So we have:
</span><span>
First way. So let's take the number 10 and explain this problem using triangles. Let's say that we have 10 triangles in the beginning:
</span>Δ Δ Δ Δ Δ
Δ Δ Δ Δ Δ
So I want to take away 3 triangles, then by taking away 3<em> what is left? </em>Well the answer is 7:
Δ Δ Δ Δ Δ
Δ Δ
That is, if we subtract 3 from 10 then the result is:
Second way. In this subtraction we take the same 10 triangles:
Δ Δ Δ Δ Δ
Δ Δ Δ Δ Δ
Now I want to take away 7 triangles, then by taking away 7 what is left is 3:
Δ Δ Δ
That is, if we subtract 7 from 10 then the result is:
</span><span>
First way. So let's take the number 10 and explain this problem using triangles. Let's say that we have 10 triangles in the beginning:
</span>Δ Δ Δ Δ Δ
Δ Δ Δ Δ Δ
So I want to take away 3 triangles, then by taking away 3<em> what is left? </em>Well the answer is 7:
Δ Δ Δ Δ Δ
Δ Δ
That is, if we subtract 3 from 10 then the result is:
Second way. In this subtraction we take the same 10 triangles:
Δ Δ Δ Δ Δ
Δ Δ Δ Δ Δ
Now I want to take away 7 triangles, then by taking away 7 what is left is 3:
Δ Δ Δ
That is, if we subtract 7 from 10 then the result is: