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.