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

Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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