Х - Олях+7 - Катях-3 - Машах+х+7+х-3=253х=21х=77-3=4 ракушки Маша<span>.......................................</span>
А)(2/9+5/9)+2/3=7/9+2/3=7/9+6/9=13/9=1 4/9
б)(0,8+(-1/6))+(-2 1/30)=(8/10-1/6)-2 1/30=(24/30-5/30)-2 1/30=19/30-
2 1/30=19/30-61/30=-42/30=-1 12/30=-1 2/5=-1,4
в)(3/7+(-8/7))+3 6/7=(3/7-8/7)+3 6/7=-5/7+3 6/7=3 1/7
г)(2,2+(-1/3))+(-3 1/15)=22/10-1/3-46/15=66/30-10/30-92/30=-36/30=
-1 6/30=-1 1/5=-1,2