1/3+1/3=2/3
4/9+3/9=7/9
1/8+4/8=5/8
3/10+6/10=9/10
3/5+2/5=5/5=1
1/9+7/9=8/9
3/6+1/6=4/6
5/10+3/10=8/10
3/7+4/7=7/7=1
5/12+7/12=12/12=1
5/8+2/8=7/8
2/12+5/12=7/12
<span>1)1/3 а-b при а =12, b=2/3
</span>
![\frac{1}{3} *12+ \frac{2}{3} = \frac{14}{3} = 4 \frac{2}{3}](https://tex.z-dn.net/?f=%20%5Cfrac%7B1%7D%7B3%7D%20%2A12%2B%20%5Cfrac%7B2%7D%7B3%7D%20%3D%20%5Cfrac%7B14%7D%7B3%7D%20%3D%204%20%5Cfrac%7B2%7D%7B3%7D%20)
<span>
2)m-2n, при m=-5</span>,n=1/2
![-5-2* \frac{1}{2} =-5-1=-6](https://tex.z-dn.net/?f=-5-2%2A%20%5Cfrac%7B1%7D%7B2%7D%20%3D-5-1%3D-6)
3)х+5/у при х=-4,2, у=2
![-4,2+ \frac{5}{2} = -4,2+2,5 =-1,7](https://tex.z-dn.net/?f=-4%2C2%2B%20%5Cfrac%7B5%7D%7B2%7D%20%3D%20-4%2C2%2B2%2C5%20%3D-1%2C7)
ИЛИ
![\frac{-4,2+5}{2} = \frac{0,8}{2}=0,4](https://tex.z-dn.net/?f=%20%5Cfrac%7B-4%2C2%2B5%7D%7B2%7D%20%3D%20%5Cfrac%7B0%2C8%7D%7B2%7D%3D0%2C4%20)
4)х-3/у при х=-1,6,у=2,3
![\frac{-1,6-3}{2.3} = \frac{-4,6}{2,3} =-2](https://tex.z-dn.net/?f=%20%20%5Cfrac%7B-1%2C6-3%7D%7B2.3%7D%20%3D%20%5Cfrac%7B-4%2C6%7D%7B2%2C3%7D%20%3D-2)
(2/3*4/5)*(3/4*5/6)*(6/7*8/9)*(7/8*9/10)=2/3*4/5*3/4*5/6*6/7*8/9*7/8*9/10=
=2/3*4*3/4*5*8/9*1/8*9/10=2*5*1/9*9/10=2*5/10=10/10=1
1)74-20=54
2)54:9=6
3)6х7=42
4)32+42=74