Estimate
Add Whole Numbers
Subtract Whole Numbers
Subtract Across Zeros
100

5,323 + 2,611 = 

8,000

100

148 + 157 = 

305

100

289 - 145 = 

144

100

400 - 215 = 

185

200

4,225 + 98 = 

4,300

200

371 + 454 = 

825

200

525 - 267 = 

258

200

5,000 - 2,058 =

2,942

300

49,761 + 59,499 = 

110,000

300

14,312 + 9,617 =

23,929

300

9,128 - 3,753 =

5,375

300

22,700 - 20,487 =

2,213

400

738,775 + 272,044 = 

1,000,000

400

5,801 + 4,189 = 

9,990

400

42,648 - 8,169 = 

34,479

400

50,000 - 6,826 =

43,174

500

542,817 - 27,398 =

470,000

500

275,558 + 605,131 = 

880,689

500

215,714 - 176,313 = 

39,401

500

900,000 - 54,862 = 

845,138