Fractions Fundamentals: Reducing Fractions

Some fractions are equal. For example, 1/2 is equal to 2/4:

1 / 2

plus White Box equals White Box White Box White Box

2 / 4

plus White Box equals White Box White Box White Box

2/3 is equal to 4/6:

2 / 3

plus White Box White Box equals White Box White Box White Box White Box White Box

4 / 6

plus White Box White Box equals White Box White Box White Box White Box White Box

How can we reduce 2/4 to 1/2?