How many groups of 2/5 are there in 4/5

Question

How many groups of 2/5 are there in 4/5. My elementary students, can you figure it out. Use a model to show.

I can’t wait to see those answers.

Answer 1

We want to find the value of x, where x is the number of groups of 2/5 in 4/5

2/5 * x = 4/5

×= 4/5 ÷ 2/5

×= 4/5 * 5/2

×= 20/10

x= 2

Answer 2

Simpler example: How many 10s are in 100 => 10 of them, since 10 * 10 = 100 or 100 / 10 = 10

Now, 2/5 * x = 4/5 => we multiply by 5/2 => x = 4/5 * 5/2 = 20 / 10 = 2

[or 2/5 * 2/1 = 4/5 => 2 groups of 2/5 are in 4/5 ]

The easier way to understand without all these calculations:

2/5 + 2/5 = 4/5 => we need two of 2/5 for 4/5

So 2 groups of 2/5 are in 4/5.