1) 6 8/15 -4 21/45 =98/15-201/45=294/45-201/45=93/45
2) 93/45*4,5=93/45*9/2=93/10
3) 2 1/6 :0,52= 13/6 :13/25=13/6*25/16=25/6
4) 93/10-25/6=279/30-125/30=154/30=5 4/30 =5 2/15
11a+9a+5a=25a
4y+16y-5y=15y
y+6y+y=8y
45x-15x-6x=24x
74a+6a-40a=40a
6k+12+4k=10k+12
35x+9+15x=50x+9
54y-34y+33=20y+33
19x+55+21x=40x+55
88x+12x-22=100x-22
9*x*50=450x
a*25*4=100a
6*x*7*3=126x
(121/11)*x=11x
5*19*a=95a
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