Подскажите . вычислите 11/12-2/3; 3/4+5/12; 2/25+1/20; 5/21-3/14.вычислите. 2/15+(1/15+1/3; 1/20+2/15+3/20+1/15; 3/4+2/3-17/12.

11/12-2/3=11/12-8/12=3/12=1/4; 3/4+5/12=9/12+5/12=14/12=1 2/12=1 1/6; 2/25+1/20=8/100+5/100=14/100=7/50; 5/21-3/14=10/42-9/42=1/42; 2/15+(1/15+1/3)=2/15+(1/15+5/15)=2/15+6/15=8/15; 1/20+2/15+3/20+1/15=1/20+3/20+2/15+1/15=4/20+3/15=1/5+1/5=2/5; 3/4+2/3-17/12=9/12+8/12-17/12=17/12-17/12=0.