<span>а) (1 цел. минус 3/4) *(4/5 -3/4)=1/80</span>
<span>1)4/5 -3/4=1/20</span>
<span>2)1 цел. - 3/4=1/4</span>
<span>3)1/4*1/20=1/80</span>
<span><span>б) 1/6 * 2/5 + 3/5 * 1/9=2/15</span></span>
<span><span>1)1/6 * 2/5=1/15</span></span>
<span><span>2)3/5*1/9=1/15</span></span>
<span><span>3)1/15+1/15=2/15</span></span>
<span><span><span>в)14 *(1/2+1/3+1/4)=15цел1/6</span></span></span>
<span><span><span>1)1/2+1/3+1/4=13/12</span></span></span>
<span><span><span>2)14*13/12=14/1*13/16(14 и 16 сокращем по 2)= 91/6=15цел1/6</span></span></span>
<span><span><span><span>г)1/3 * 6/7 - 1/7 * 3/4=5/28</span></span></span></span>
<span><span><span><span>1)1/3*6/7=2/7</span></span></span></span>
<span><span><span><span>2)1/7*3/4=3/28</span></span></span></span>
<span><span><span><span>3)2/7-3/28=5/28</span></span></span></span>