Sums and Differences of Decimals

Video Lessons and Solutions to help Grade 6 students learn how to add and subtract multi-digit decimals.

New York State Common Core Math Module 2, Grade 6, Lesson 9

Worksheets for Grade 6

Lesson 9 Student Outcomes

• Students relate decimals to mixed numbers and round addends, minuends, and subtrahends to whole numbers in order to predict reasonable answers.
• Students use their knowledge of adding and subtracting multi-digit numbers to find the sums and differences of decimals.
• Students understand the importance of place value and solve problems in real-world contexts.

Classwork
Example 1
25 3/10 + 376 77/100
Example 2
426 1/5 - 275 1/2

Exercises 1–5
Calculate each sum or difference.

1. Samantha and her friends are going on a road trip that is 245 7/50 miles long. They have already driven 128 53/100 How much further do they have to drive?
   
   
2. Ben needs to replace two sides of his fence. One side is 367 9/100 meters long, and the other is 329 3/10 meters long. How much fence does Ben need to buy?
   
   
3. Mike wants to paint his new office with two different colors. If he needs 4 4/5 gallons of red paint and 3 1/10 gallons of brown paint, how much paint does he need in total?
   
   
4. After Arianna completed some work, she figured she still had 78 1/200 pictures to paint. If she completed another 34 23/25 pictures, how many pictures does Arianna still have to paint?
   
   Use a calculator to convert the fractions into decimals before calculating the sum or difference.
   
5. Rahzel wants to determine how much gasoline he and his wife use in a month. He calculated that he used 78 1/3 gallons of gas last month. Rahzel’s wife used 41 3/8 gallons of gas last month. How much total gas did Rahzel and his wife use last month? Round your answer to the nearest hundredth.

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Example 1
25 3/10 + 376 77/100
Example 2
426 1/5 - 275 1/2

• Show Step-by-step Solutions

Problem Set

1. Find each sum or difference.
   a. 381 1/10 - 214 43/100
   b. 32 3/4 - 12 1/2
   c. 517 37/50 + 312 3/100
   d. 632 16/25 + 32 3/10
   e. 421 3/50 - 212 9/10
   
   
2. Use a calculator to find each sum or difference. Round your answer to the nearest hundredth.
   a. 422 3/7 - 367 5/9
   b. 23 1/5 + 45 7/8

• Show Step-by-step Solutions

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