Suppose a die is tossed 10 times. Let $X$ be the number of ones and let $Y$ be the number of sixes.

How would you find the probability that $P\left(X+Y=4\right)$?

My attempt so far:

Applying the Binomial Distribution, I can find the probability that $X$ or $Y$ equals $4$, but I do not know how to put these pieces together to find $P\left(X+Y=4\right)$.