Question 163025
Just take your two terms and reduce them to their factors:
2x^2y^3 = 2∙x∙x∙y∙y∙y
10x^2y = 2∙5∙x∙x∙y
And remove their common factors, 
So you have the factors common to each (cross them out as you go)…
2∙x∙x∙y , which is 2x^2y, which is your  answer.

Good luck.