Unit 01 · Whole Numbers and DecimalsLesson

Day 004Subtracting Decimals

LearnClassworkAnswer keyPDF packet ↗
Standards 6.NS.B.3
LEARNING TARGET

I can subtract decimals and explain regrouping.

Build the idea

Align decimal points and add placeholder zeros. Regroup one whole as ten tenths, or one tenth as ten hundredths. Subtract by place and check by adding the difference to the subtrahend.

WORKED EXAMPLE 1

Use the standard algorithm: 88.6 - 8.8. Show your regrouping or division steps.

79.8

Align decimal points; 88.6 - 8.8 = 79.8.

WORKED EXAMPLE 2

Use the standard algorithm: 3.22 - 0.48. Show your regrouping or division steps.

2.74

Align decimal points; 3.22 - 0.48 = 2.74.

Your turn

Work in order. Start with the foundations, then build toward explanation and application.

  1. Use the standard algorithm: 65.1 - 7.8. Show your regrouping or division steps.

  2. Use the standard algorithm: 83.1 - 5.3. Show your regrouping or division steps.

  3. Use the standard algorithm: 21 - 1.5. Show your regrouping or division steps.

  4. Use the standard algorithm: 6 - 3.77. Show your regrouping or division steps.

  5. Use the standard algorithm: 8.13 - 6.6. Show your regrouping or division steps.

  6. Use the standard algorithm: 4.25 - 3.3. Show your regrouping or division steps.

  7. Use the standard algorithm: 3.27 - 0.44. Show your regrouping or division steps.

  8. Use the standard algorithm: 9.14 - 0.87. Show your regrouping or division steps.

  9. A tank holds 7.85 L. A class uses 0.15 L. How much remains?

  10. A tank holds 4.73 L. A class uses 0.79 L. How much remains?

Answers and reasoning

Reveal the teacher answer key
  1. 57.3

    Align decimal points; 65.1 - 7.8 = 57.3.

  2. 77.8

    Align decimal points; 83.1 - 5.3 = 77.8.

  3. 19.5

    Align decimal points; 21 - 1.5 = 19.5.

  4. 2.23

    Align decimal points; 6 - 3.77 = 2.23.

  5. 1.53

    Align decimal points; 8.13 - 6.6 = 1.53.

  6. 0.95

    Align decimal points; 4.25 - 3.3 = 0.95.

  7. 2.83

    Align decimal points; 3.27 - 0.44 = 2.83.

  8. 8.27

    Align decimal points; 9.14 - 0.87 = 8.27.

  9. 7.7 L

    Align decimal points; 7.85 - 0.15 = 7.7.

  10. 3.94 L

    Align decimal points; 4.73 - 0.79 = 3.94.

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