1)0,9:2,25=90:225=0,4
2)0,75*0,064=0,048
3)0,4-0,048=0,352
4)0,2816:0,352=281,6:352=0,8
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5)4 1/8:7=33/8:7/1=33/56
6)2 3/40-33/56=2 21/280-165/280=416/280=1 17/35
7)1,3=1 3/10:1 17/35=13/10:52/35=7/8
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8)0,8:7/8=8/10=4/5:7/8=32/35
9)32/35*4 13/16=32/35*77/16=22/5=4 2/5=4,4