Please explain why you divide by 100 in this problem

Question

I have 200 men, and 800 women, who eat 1200 bags of chips. Also, I have 100 men and 400 women, who eat 1100 bags. Let m = bags ate by men, and let w = bags ate by women.  200m + 300w =1200. The Khan academy video I watched said to do the following. Video source: Systems of equations with substitution: potato chips.  They said: 100m + 400w=1100m=100m/100=-400w/100 +1100/100.  Where or how did they decide to divide by 100, with 400w and 1100 men?

Answer 1

Because all the numbers involved are multiples of 100, dividing by 100 simplifies the equations and makes them easier to solve.