Упражнение №1091
Выполните действия:
1) 5/6*9/15-5/12*4/15=7/18
1. 5/6*9/15=5*9/6*15=1*3/2*3=1/2
2. 5/12*4/15=5*4/12*15=1*1/3*3=1/9
3. 1/2-1/9=9*1/9*2-2*1/2*9=9/18-2/18=7/18
2) 7/18*9/14+1/3*6/7=15/28
1. 7/18*9/14=7*9/18*14=1*1/2*2=1/4
2. 1/3*6/7=1*6/3*7=2/7
3. 1/4+2/7=7*1/7*4+4*2/4*7=7/28+8/28=15/28
3) 9/20*2/3+5/14*7/25=2/5
1. 9/20*2/3=9*2/20*3=3*1/10*1=3/10
2. 5/14*7/25=5*7/14*25=1*1/2*5=1/10
3. 3/10+1/10=4/10=2/5
4) 3 3/4*2/5-3 6/25*5/27=9/10
1. 3 3/4*2/5=15/4*2/5=15*2/4*5=3*1/2*1=3/2
2. 3 6/25*5/27=81/25*5/27=81*5/25*27=3*1/5*1=3/5
3. 3/2-3/5=5*3/5*2-2*3/2*5=15/10-6/10=9/10
5) 2 2/5*5/6-3/4*1 2/3=3/4
1. 2 2/5*5/6=12/5*5/6=12*5/5*6=2
2. 3/4*1 2/3=3/4*5/3=3*5/4*3=5/4
2. 2-5/4=8/4-5/4=3/4
6) 1 17/28*14/9+14/25*5/7= 2 9/10
1. 1 17/28*14/9=45/28*14/9=45*14/28*9=5*1/2*1=5/2
2. 14/25*5/7=14*5/25*7=2*1/5*1=2/5
3. 5/2+2/5=5*5/5*2 + 2*2/2*5=25/10 + 4/10=29/10=2 9/10