# Lesson 21 Zeros in the Standard Algorithm

• Let’s subtract from numbers with several zeros.

## Warm-up Which One Doesn’t Belong: Numbers with 0, 2, and 5

Which one doesn’t belong?

1. 2,050

2. 2,055

3. 205.2

4. 20,005

## Problem 1

Here are some numbers you saw earlier. Each number has at least one 0. From each number, 1,436 is being subtracted.
Make sense of the problems and explain to a partner.

## Problem 2

Use the approach in the first problem to find these two differences:

## Problem 3

Find the value of each difference. Be prepared to explain your reasoning. If you get stuck, try subtracting using the expanded form.

## Activity 2 What is Your Age?

Jada recorded the birth year of some of her maternal grandparents for a family history project.

family member

birth year

grandmother

1952

grandfather

1948

great-grandmother

1930

great-grandfather

1926

As of this year, what is the age of each family member? Show your reasoning. Use the standard algorithm at least once.

## Problem 1

Here is how Han found

1. How can you tell by estimating that Han has made an error?

2. What error did Han make?

3. Find the value of .