K-5 friendly lesson
One small step at a time.Read the idea, try the activity, and celebrate each win as you go.
Add Two-Digit Numbers: Regrouping! sums up to 100
π¨ What happens when the answer is too big to fit in the ones column? We have to carry it over the wall to the tens side! This is the most famous math trick ever.
Do this: Read the concept below, then try the quiz or activity.
Lesson 50 of 186
Concept
This is the famous "Carry the One" rule! If you learn this, you can add any numbers in the universe.
π― The Regrouping "Carry" Rule: Example: 46 + 28 = ? 1. Stack: 4 6 + 2 8 --------- 2. Add Ones: 6 + 8 = 14. Uh oh. You can't write 14 under the ones column! A column can only hold one digit (0-9). 3. The Trick: The number 14 is made of 1 ten and 4 ones. * Write the 4 at the bottom of the Ones column. * Take the 1 ten and "carry it" up to the very top of the Tens column! Write a little +1 floating above the 4. 4. Add Tens: Now you have to add THREE numbers down the Tens column! The little +1, the 4, and the 2. (1 + 4 + 2 = 7!) 5. Answer: 74!
Try it
Carry the 1!
Instructions: Add the Ones first. If it's 10 or more, carry the "1" to the top of the Tens column!
Problem 1: +1 (Carry!) 5 7 + 2 5 --------- * Ones: 7 + 5 = 12. Write the 2 at the bottom, carry the 1! * Tens: 1 + 5 + 2 = ___ * Total Answer: ___
Problem 2: 3 6 + 4 8 --------- * Answer: ___
Problem 3: 6 9 + 1 4 --------- * Answer: ___
Problem 4: 2 8 + 5 3 --------- * Answer: ___