72.8/5.6+14.9 0.25X3.2X12.5 6.25/1.25/0.8 42X10.1—4.2全部简便计算
2个回答

72.8÷5.6+14.9

= 728÷56+14.9

= 13 + 14.9

= 27.9

0.25×3.2×12.5

= 0.25×(4×0.8)×12.5

= (0.25×4)×(0.8×12.5)

=1×10

=10

6.25÷1.25÷0.8

=6.25÷(1.25×0.8)

=6.25÷1

= 6.25

42×10.1—4.2

=4.2×101—4.2×1

= 4.2×(101-1)

= 4.2×100

= 420