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Grade 2 Math · World 6: Thousand Tower · Level 51
Adding and Subtracting Hundreds
300 + 400, 700 − 200, 450 + 100.
Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.
What children learn in Level 51
- Adding hundreds is just like adding ones. 300 plus 400: that's 3 hundreds and 4 hundreds.
- 3 plus 4 is 7, so 3 hundreds plus 4 hundreds is 7 hundreds: 700!
- Taking away works the same way. Here's 700 minus 200. Tap 2 hundreds to take them away!
- 5 hundreds are left. 700 minus 200 is 500, just like 7 minus 2 is 5.
- What about 450 plus 100? Add one hundred: only the hundreds digit changes. 450 plus 100 is 550!
Georgia's K-12 Mathematics Standards:
- 2.NR.2 — Apply multiple part-whole strategies, properties of operations and place value understanding to solve real-life, mathematical problems involving addition and subtraction within 1,000.
- 2.NR.2.2 — Find 10 more or 10 less than a given three-digit number and find 100 more or 100 less than a given three-digit number.