Unit 03 · Ratios and MeasurementLesson

Day 037Double Number Lines

LearnClassworkAnswer keyPDF packet ↗
Standards 6.RP.A.3a
LEARNING TARGET

I can represent a ratio on a double number line.

Build the idea

Place zero on both parallel number lines. Align a known pair above and below one tick. Add equal jumps on each line so aligned values remain in the same ratio.

WORKED EXAMPLE 1

Draw aligned number lines for 6 liters of paint covering 4 square meters. Mark 0, one batch, and 6 batches. How much area do 36 liters cover?

24 square meters; aligned pairs (0,0), (6,4), (36,24)

36 ÷ 6 = 6 batches; 6 × 4 = 24.

WORKED EXAMPLE 2

Draw aligned number lines for 5 liters of paint covering 5 square meters. Mark 0, one batch, and 5 batches. How much area do 25 liters cover?

25 square meters; aligned pairs (0,0), (5,5), (25,25)

25 ÷ 5 = 5 batches; 5 × 5 = 25.

Your turn

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

  1. Draw aligned number lines for 7 liters of paint covering 7 square meters. Mark 0, one batch, and 3 batches. How much area do 21 liters cover?

  2. Draw aligned number lines for 3 liters of paint covering 3 square meters. Mark 0, one batch, and 3 batches. How much area do 9 liters cover?

  3. Draw aligned number lines for 2 liters of paint covering 7 square meters. Mark 0, one batch, and 4 batches. How much area do 8 liters cover?

  4. Draw aligned number lines for 7 liters of paint covering 2 square meters. Mark 0, one batch, and 3 batches. How much area do 21 liters cover?

  5. Draw aligned number lines for 3 liters of paint covering 6 square meters. Mark 0, one batch, and 6 batches. How much area do 18 liters cover?

  6. Draw aligned number lines for 6 liters of paint covering 4 square meters. Mark 0, one batch, and 5 batches. How much area do 30 liters cover?

  7. Draw aligned number lines for 7 liters of paint covering 7 square meters. Mark 0, one batch, and 4 batches. How much area do 28 liters cover?

  8. Draw aligned number lines for 5 liters of paint covering 7 square meters. Mark 0, one batch, and 6 batches. How much area do 30 liters cover?

  9. Draw aligned number lines for 3 liters of paint covering 3 square meters. Mark 0, one batch, and 4 batches. How much area do 12 liters cover?

  10. Draw aligned number lines for 4 liters of paint covering 7 square meters. Mark 0, one batch, and 7 batches. How much area do 28 liters cover?

Answers and reasoning

Reveal the teacher answer key
  1. 21 square meters; aligned pairs (0,0), (7,7), (21,21)

    21 ÷ 7 = 3 batches; 3 × 7 = 21.

  2. 9 square meters; aligned pairs (0,0), (3,3), (9,9)

    9 ÷ 3 = 3 batches; 3 × 3 = 9.

  3. 28 square meters; aligned pairs (0,0), (2,7), (8,28)

    8 ÷ 2 = 4 batches; 4 × 7 = 28.

  4. 6 square meters; aligned pairs (0,0), (7,2), (21,6)

    21 ÷ 7 = 3 batches; 3 × 2 = 6.

  5. 36 square meters; aligned pairs (0,0), (3,6), (18,36)

    18 ÷ 3 = 6 batches; 6 × 6 = 36.

  6. 20 square meters; aligned pairs (0,0), (6,4), (30,20)

    30 ÷ 6 = 5 batches; 5 × 4 = 20.

  7. 28 square meters; aligned pairs (0,0), (7,7), (28,28)

    28 ÷ 7 = 4 batches; 4 × 7 = 28.

  8. 42 square meters; aligned pairs (0,0), (5,7), (30,42)

    30 ÷ 5 = 6 batches; 6 × 7 = 42.

  9. 12 square meters; aligned pairs (0,0), (3,3), (12,12)

    12 ÷ 3 = 4 batches; 4 × 3 = 12.

  10. 49 square meters; aligned pairs (0,0), (4,7), (28,49)

    28 ÷ 4 = 7 batches; 7 × 7 = 49.

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