24×5=
91+199=
7.8+2.2=
5.3﹣2.7=
9÷0.1=
2.5×0.4=
+0.25=
× =
40×20=(4×10)×(2×10)=(4×2)×(10×10)=8×100=800
0.4×0.2=(4×0.1)×(2×0.1)=( × )×( × )= ×
=(4× )×(2× )=( × )×( × )= ×
①0.4x=3.6
②x﹣x=70
③1.6:x=0.8:0.4
④=