Mental Math: Addition

To find the sum using an open number line for:

236 + 1 43

• Start with 236 and jump 100 then 40 then 3

• Start with 236 and jump 200 then 30 then 6

• Strat with 236 and add 236

• Start with 143 and jump 100 then 40 then 3

408 + 261 =

• 469

• 668

• 669

• 269

Using make ten strategy, the first step to find 348 + 126 is:

• 348 + 20

• 348 + 100

• 348 + 2

• 248 + 6

Using make ten strategy, the first step to find 257 + 115 is:

• 257 + 3

• 257 + 5

• 257 + 100

• 257 + 10

Using make ten strategy, to find 246 + 135 I will follow the steps:

• 246 + 4 = 250

  250 + 100 =350

  350 + 30 = 380

  380 + 1 = 381

• 246 + 100 = 346

• 246 + 4 = 250

  250 + 100 =350

  350 + 30 = 380

  380 + 5 = 385

To find 325 + 168 using make ten strategy, I will follow the steps:

• 325 + 5 = 330

  330 + 100 =430

  430 + 60 = 490

  490 + 8 = 498

• 325 + 5 = 330

  330 + 100 =430

  430 + 60 = 490

  490 + 3 = 493

• 325 + 5 = 330

  330 + 100 =430

  490 + 8 = 498