Add 3 Digit Numbers Mentally

Use compatible numbers. Estimate to find the sum. 
124 + 149=

• 300

• 275

• 273

• 175

Add or subtract mentally:

396 + 75 =

• 470

• 461

• 471

• 475

Tags

CCSS.2.NBT.B.5

Add mentally:

256 + 203 [1 Mark]

Tags

CCSS.2.NBT.B.5

Use mental math to add 132 + 122 =

Type your answer.

Tags

CCSS.4.NBT.B.4

Question 2: Add 456 and 189. What is the result?

• 543

• 645

• 732

• 625

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2

Find the total when 523 and 367 are added together.

• 456

• 890

• 8900

• 1000

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2

What is the sum of 345 and 278?

• 423

• 567

• 623

• 512

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2

Add mentally.
721 + 136

• 757

• 857

• 957

• 777

Tags

CCSS.2.NBT.B.5

Add mentally. 846 + 100 = ?

• 946

• 846

• 746

• 546

Tags

CCSS.2.NBT.B.5

What is the sum of 345 and 278?

• 423

• 567

• 623

• 512

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2