45.
1) (2/5)+1,83=0,4+1,83=2,23
2) 6,4 - (3/20)=6,4 - 0,15= 6,25
3) 9,8·(3/10)=9,8·0,3=2,94
4) 7,2:(1/100)=7,2:0,01=720:1=720
46.
1) 8,5 - (1/3)=8 целых 1/2 - (1/3)=(17/2)-(1/3)=(51/6)-(2/6)=(49/6)=
=8 целых 1/6
2) 4 целых 1/9 +1,8 = (37/9) +(18/10)=(37/9)+(9/5)=(185/45)+(81/45)=
=266/45=5 целых 41/45
3) (1/9)·0,2=(1/9)·(2/10)=2/90=1/45
4) (6/7):0,6=(6/7)·10/6=10/7=1 целая 3/7