⑴12:4=6:x
⑵x:5=2.5:0.1
⑶:x:
⑷
13.7-3.6-4.3-2.1
0.59×101
2.5×12.5×40×0.8
()×24
24×+75÷5+
9×3.45+11.1×180%+54.3÷
①0.96×÷ ②÷4+4÷ ③2019×
④×13+×25 ⑤(+2.1)×÷0.9 ⑥0.5+÷(0.75+)
①5.4+2x=8.6
②2.5∶5=x∶8
③0.2=1-