Helena lost her marbles. But then she found them and put them in 4 bags with m marbles in each bag. She had 3 marbles left over that didn't fit in the bags. How many marbles does Helena have in all?

For this case, the first thing we must do is define a variable:

m = number of marbles

We have then:

"put them in 4 bags with m marbles in each bag"

mathematically we have:

4m

Then,

"She had 3 marbles left over that did not fit in the bags"

mathematically we have:

4m + 3

Answer:

Helena has:

4m + 3 marbles.