# The Stamp Collection

## Task

Masha had $120$ stamps. First, she gave her sister half of the stamps and then she used three to mail letters. How many stamps does Masha have left?

## IM Commentary

This task uses language, "half of the stamps," that students in Grade 5 will come to associate with multiplication by the fraction $\frac12$. In Grade 3, many students will understand half of 120 to mean the number obtained by dividing 120 by 2. For students who are unfamiliar with this language the task provides a preparation for the later understanding that a fraction of a quantity is that fraction times the quantity.

## Solution

We can visualize the problem with a bar diagram:

2 units = 120

1 unit = 60

60 - 3 = 57

Masha had 57 stamps left.

## The Stamp Collection

Masha had $120$ stamps. First, she gave her sister half of the stamps and then she used three to mail letters. How many stamps does Masha have left?