adding a two-digit number & a multiple of 10 1.NBT.4

1. adding a two-digit number & a multiple of 10 1.NBT.4

2. 1.NBT.4 Standard Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.

3. Let’s count by tens starting with 3…..

4. 3 13 3 +10=13

5. 3 13 23 33

6. 3 +10+10+10=33

7. 10 20 + = 43 30 33 + 10

8. Let’s count by tens starting with 24…..

9. 34 = + 24 10

10. 44 = + 34 10

11. 54 = + 44 10

12. 64 = + 54 10

13. What is the pattern?

14. Now Try These 10 + 4 = 14

15. Now Try These 20 + 4 = 24

16. Now Try These 30 + 4 = 34

17. Now Try These 40 + 4 = 44