6,7-х=0,78:2,6
6,7-х=0,3
х=6,7-0,3
х=6,4
1) 19 целых 3/4 + 5 целых 2/3 = 25 целых 5/12
2) P=(25 целых 5/12 + 19 целых 3/4) × 2
P= 43 целых 2/12
3/10+8.51+4/25=0.3+8.51+0.16=8.97
9.65+5 1/4+1.7=9.65+5.25+1.7=16.3
18.35+3 1/5+2.45=18.35+3.2+2.45=24
2.64+5 2/3+2/15=264/100+17/3+2/15=792/300+1700/300+40/300=2535/300=8 135/300=8 9/20
2 1/4+3.6+1\6=9/4+36/10+1/6=136/60+216/60+10/60=362/60=6 2/20=6 1/30
19.6+1/6+3 2/15=196/10+1/6+77/15=588/30+5/30+154/30=744/30=24 27/30=24 9/10