3×650-35 3×33+3+3 1米90厘米
4×530-5 4+3872-27 5米50厘米
19<+2 25>8+ 12->8
40>-20 30<6+ 19-<8
28+43= 100-45= 56+22=
72-58= 88+11= 89-41=