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Round to the nearest 10
Adding tens to a 2 digit number
Estimate the sum to the nearest 10
Estimate the difference to the nearest 10
Subtracting tens to a 2 digit number
100
23
20
100

41+30=

41,___,____,____

41+30=71

100

Estimate:

43+26=

40+30=70

100

Estimate:

38-26=

40-30=10

100

75-20=

75, 65,____

75-20=55

200
57
60
200

46+20=

46,____,____

46+20=66

200

Estimate:

23+37=

20+40=60

200

Estimate:

33-21=

30-20=10

200

67-40=

67,___,____,_____,_____

67-40=27

300

76

80

300

29+30=

29,___,____,_____

29+30=59

300

Estimate:

29+33=

30+30=60

300

Estimate:

88-32=

90-30=60

300

56-20=

56-20=36

400

92

90

400

53+40=

53+40=93

400

Estimate:

52+12=

50+10=60

400

Estimate:

57-14=

60-10=50

400

71-30=

71-30=41

500

17

20

500

53+20=

53+20=73

500

Estimate:

37+32=

40+30=70

500

Estimate:

81-28=

80-30=50

500

98-60=

98-60=38