#13
100*2/5=40(см)
100*2/3=66 2/3(см)
40*66 2/3=266 2/3(см^2)
#14
1/3*2=2/3
1/3*0,5=1/6
1/3*3/4=1/4
#15
100*3/4=75(см)
100см-96р
75см-x
100x=7200:100
x=72(р)
100*2/3=66 2/3(см)
100-96
66 2/3- x
100x=6400:100
x=64
#16
3/4-3
100-x
3/4x=300:3/4
x=400
#17
60*2/5=24
#18
42*3/7=18