### Home > MC2 > Chapter 3 > Lesson 3.2.4 > Problem 3-99

Think about the mathematical process you use as you solve the following problems. Show your work and your solutions.

If there are

students in a room and of them are boys, how many are girls? Since there are

boys out of students, the rest of the students have to be girls. So subtract from to get the number of girls. girls If there are

blue and white stripes on a flag and of them are blue, how many are white? See part (a).

If there are

pennies and dimes in a box and of them are pennies, how many are dimes? See part (a).

Now it is time to generalize. Imagine you know how many items you have in a collection of two types of things. If you know how many of one of the items you have, how could you find how many of the other item you have?

Describe the process used in part (a).