<span>5/6 -4/9=15/18-8/18=7/18
</span><span>3 1/8+2 5/6=5+1/8+5/6=5+3/24+20/24=5 23/24
</span><span>5 11/12- 3 7/18=2 +(11/12-7/18)=2+(33/36-14/36)=2+19/36=2 19/36</span><span>
</span>
<span>(а-5)²-а(-10-2а)
= a²-10a+25 +10a+2a² =</span><span> 3a²+25</span>
1 11м 7дм
2 420
3 328
4 1600см2
5 800дм2
6 5дм2
1-13/55=55/55-13/55=42/55
6-9/20=5 20/20-9/20=5 11/20
10-5 12/35=9 35/35-5 12/35=4 23/35
8-4 5/22=7 22/22-4 5/22=3 17/22.