Make a Number Using Subtraction - Up to 20
🧩 Be a math inventor! There isn't just one way to make a number. You can find dozens of different subtraction sentences that all equal the same answer.
Do this: Read the concept below, then try the quiz or activity.
Concept
If your teacher asks you to "Make the number 8 using subtraction," how many ways can you do it? A lot! You just have to follow a pattern.
🎯 The "Step Up" Pattern: Let's make the number 8! 1. Start easy: What minus 0 equals 8? (8 - 0 = 8) 2. Step up both numbers by 1: (9 - 1 = 8) 3. Step up by 1 again: (10 - 2 = 8) 4. Keep going! (11 - 3 = 8), (12 - 4 = 8), (13 - 5 = 8)...
As long as you increase BOTH the starting number AND the number you take away by exactly the same amount, the answer (the difference) will always stay exactly the same!
Try it
Let's invent some subtraction sentences!
Instructions: Find different ways to make the target number using subtraction.
Target Number: 10 1. 10 - 0 = ___ 2. 12 - ___ = 10 3. 15 - ___ = 10 4. 20 - ___ = 10
Target Number: 7 5. 7 - 0 = 7 6. 8 - 1 = 7 7. 9 - ___ = 7 8. ___ - 3 = 7
Challenge: Write your own subtraction sentence that equals 5! 9. ___ - ___ = 5