Mental Math Tricks

Trick 1: Adding 10

46 + 10

Tags

CCSS.2.NBT.B.7

Trick 1: Adding 10

46 + 20

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2

Trick 1: Adding 10

729 + 100

Tags

CCSS.2.NBT.B.7

Trick 1: Adding 10

850 + 200

Tags

CCSS.6.NS.B.3

Trick 2: Make Ten

Match the following complements (numbers that go together to make 10)

• 9

• 5 and ___ make 10

• 7

• 3 and ___ make 10

• 6

• 4 and ___ make 10

• 5

• 2 and ___ make 10

• 8

• 1 and ___ make 10

Tags

CCSS.1.OA.A.1

Trick 2: Make Ten

Use the Make Ten trick to answer the following problem mentally

16 + 14

Trick 2: Make Ten

Use the Make Ten trick to answer the following problem mentally

43 + 47

Tags

CCSS.1.NBT.C.4

CCSS.2.MD.B.6

Trick 2: Make Ten

Use the Make Ten trick to answer the following problem mentally

8 + 5 + 2 + 5

Trick 2: Make Ten

Use the Make Ten trick to answer the following problem mentally

13 + 19 + 17 + 11

Trick 3: Subtraction Into Addition

23 - 15

Change the question to "How much would you have to add to 15 to get 23?"

15 + ​ (a)   = 20

20 + ​ (b)   =23

Since 5 + 3 = ​ (c)   , we know we have to add a total of ​ (d)   to get to 23.

• 5
• 3
• 8

Tags

CCSS.2.OA.A.1