📏 Part 1: Number Line Subtraction

Remember: To subtract, start at the first number and count backwards (move left) on the number line.

Number line: 0 ─ 1 ─ 2 ─ 3 ─ 4 ─ 5 ─ 6 ─ 7 ─ 8 ─ 9 ─ 10 ─ 11 ─ 12 ─ 13 ─ 14 ─ 15 ─ 16 ─ 17 ─ 18 ─ 19 ─ 20

Answer: 18 - 5 = _____

Number line: 15 ─ 16 ─ 17 ─ 18 ─ 19 ─ 20 ─ 21 ─ 22 ─ 23 ─ 24 ─ 25 ─ 26 ─ 27 ─ 28 ─ 29 ─ 30

Answer: 25 - 8 = _____

Start at 42. First jump back _____ to get to _____. Then jump back _____ to get to _____.

Answer: 42 - 15 = _____

Number line: 5.0 ─ 5.5 ─ 6.0 ─ 6.5 ─ 7.0 ─ 7.5 ─ 8.0 ─ 8.5 ─ 9.0

Answer: 7.8 - 2.3 = _____

🔄 Part 2: Addition and Subtraction Connection

Remember: Addition and subtraction are inverse operations. You can check subtraction with addition!

If 12 - 7 = 5, then:

5 + 7 = _____

12 - 5 = _____

7 + 5 = _____

a) 23 - 9 = 14 Check: 14 + 9 = _____ ✓ or ✗

b) 35 - 18 = 17 Check: 17 + 18 = _____ ✓ or ✗

c) 50 - 26 = 26 Check: 26 + 26 = _____ ✓ or ✗

Subtraction: $24.50 - $8.75 = $ _____

Check with addition: $ _____ + $8.75 = $24.50

🎯 Part 3: Problem Solving

Problem: 73 - 28

My estimate (round to nearest 10): _____ - _____ = _____

Actual calculation: 73 - 28 = _____

Is my answer reasonable? Explain: ________________

Temperature dropped from 3°C to -5°C. What was the change in temperature?

Number line: -10 ─ -8 ─ -6 ─ -4 ─ -2 ─ 0 ─ 2 ─ 4 ─ 6 ─ 8 ─ 10

The temperature dropped by _____ degrees.

My problem: _____ - _____ = ?

Answer: _____