Topic D
adding and subtracting decimals
STANDARD - 5.NBT.2, 5.NBT.3, 5.NBT.7
Grade 5
Module 1 Lesson 10
Objective:
Subtract decimals using place value
strategies and relate those strategies to a
written method.
MATERIALS NEEDED
FOR THIS LESSON
Student
Student Pages
Problem Set
Exit Ticket
Homework
Place Value Chart
Personal White Boards
Teacher
Teacher Pages
Fluency Practice (10 minutes)
Take Out the Unit
3 minutes
5.NBT.1
76.358 = _____
Say the number
76.358 = 7 tens _____ thousandths
76.358 = 763 tenths _____ thousandths
76.358 = _____ hundredths 8 thousandths
Add Decimals
5.NBT.7
3 tenths + 2 tenths = _____
5 hundredths + 4 hundredths =
35 hundredths + 4 thousandths =
3 minutes
One Unit Less
5.NBT.7
What is 1 less than
5 tenths?
5 hundredths?
5 thousandths?
4 minutes
What is 1 less than
7 hundredths?
9 tenths?
Write the decimal that is one less thousandths
0.029
Write the decimal that is one tenth less
0.61
Write the decimal that is 1 thousandth less than
0.061?
Write the decimal that is 1 hundredth less than
0.549?
Application Problem (5 minutes)
At the 2012 London Olympics, Michael Phelps won the gold
medal in men's 100 meter butterfly. He swam the first 50 meters
in 26.96 seconds. the second 50 meters took him 25.39 seconds.
What was his total time?
Concept Development (35 minutes)
Problem 1
subtracting decimals
5 tenths - 3 tenths
ones
tenths
hundredths
thousandths
7 ones 5 thousandths - 2 ones 3 thousandths
ones
tenths
hundredths
thousandths
9 hundreds 5 hundredths - 3 hundredths
hundreds
tens
ones
tenths
hundredths
thousandths
Problem 2
subtracting decimals
85 tenths - 6.4
ones
tenths
hundredths
thousandths
Problem 3
subtracting decimals
9.2 - 6 ones 4 tenths
ones
tenths
hundredths
thousandths
0.831 - 0.292
ones
tenths
hundredths
thousandths
4.003 - 1.29
ones
tenths
hundredths
thousandths
6 - 4.08
ones
tenths
hundredths
thousandths
Problem Set (10 minutes)
Do Your Personal Best
(Complete independently!)
Student Debrief (10 minutes)
How is subtracting decimals fractions the same as subtracting whole
numbers? How is it different?
Look at #2 a, b, and c. What process did you use to find the
difference in each of these problems?
Did you have to use the standard algorithm to solve #3?
Look at b and c. Which one was more challenging?
In #3f, how did you think about finding the difference between
59 hundredths from 2 ones 4 tenths? Explain your approach.
EXIT TICKET (3 minutes)
Complete the exit ticket and turn in...
HOMEWORK