Show:
Round to the nearest ten
Even or odd
Ballpark estimate the sum
Ballpark estimate the difference
100
23
20
100

890

even

100
43+26=
40+30=70 43+26=69
100
63-37=
60-40=20 63-37=26
200
57
60
200

147

odd

200

54+37=

50+40=90 54+37=91

200
54-22=
50-20=30 54-22=32
300
476
480
300

678

even

300

72+19=

70+20= 90 72+19=91

300
145-56=
150-60=90 145-56=89
400
923
920
400

451

odd

400

205+406

210+410=620 205+406= 611

400
283-256=
280-260= 20 283-256= 27
500
178
180
500

555

odd


500

769+45=

770+40=810 769+445=814

500
778-356=
780-360=420 778-356=422