Вычислите дроби. 1/4+4/7+9/28 1/5+3/10+7/20 3/20+7/30+2/40 17/20+23/30+11/60
1/4+4/7+9/28=7+16+9/28=32/28=8/7 1/5+3/10+7/20=4+6+7/20=17/20 3/20+7/30+2/40=18+28+6/120=52/120 17/20+23/30+11/60=51+46+11/60=108/60=54/30