Relate Addition and Subtraction Sentences - Up to 10
🔄 Addition and subtraction are opposites, like a forward and backward button! If you add a number, you can "un-do" it by subtracting that same number. Let's explore these "Un-doers"!
Do this: Read the concept below, then try the quiz or activity.
Concept
Addition and subtraction are inverse operations.That's a fancy way of saying they undo each other.
🎯 The "Forward and Back" Rule: Think of a number line. * Addition is moving forward: If you start at 4 and add 3, you move forward to 7. * 4 + 3 = 7 * Subtraction is moving backward: Now, if you are at 7 and you subtract 3, you move backward to 4. * 7 - 3 = 4
You end up right back where you started! Subtraction undid the addition.
This works the other way too: * Start at 10, subtract 6, you get 4.(10 - 6 = 4) * From 4, add 6, you get back to 10!(4 + 6 = 10)
This is the secret behind Fact Families !The three numbers(4, 6, 10) are all connected by addition and subtraction.
Try it
Let's practice with the "Un-doers"!
Instructions: For each pair of sentences, see how they are related.
1. Forward: 5 + 2 = 7 * Backward: 7 - 2 = ___
2. Forward: 6 + 4 = 10
* Backward: 10 - 4 = ___ 3. Backward: 9 - 5 = 4
* Forward: 4 + 5 = ___ 4. Backward: 8 - 1 = 7
* Forward: 7 + 1 = ___🏆 Puzzle Challenge: Use the first sentence to instantly solve the second one!
5. If you know 3 + 7 = 10, then what is 10 - 7 ?
* Answer : ___ 6. If you know 9 - 2 = 7, then what is 7 + 2 ?
* Answer : ___ 7. Write the two subtraction sentences that are related to 2 + 8 = 10.
* 10 - ___ = ___
* 10 - ___ = ___