45+45=90
(35+35)+20=90
(25+25)+(20+20)=90
20•4+10=90
7*8=56 5*8=40 6*0=0 6*1=6 12:3=42 + 2 = 4 32:4=8 32:8=8
13/14+1/15=(13*15+1*14)/210=209/210
24/25+1/4=(24*4+1*25)/100=(96+25)/100=
=121/100=1 21/100=1,21
1/2+5/7=(1*7+5*2)/14=17/14=1 3/14
1/4+5/6=(1*3+5*2)/12=13/12. =1 1/12
3/20+7/25=(3*5+7*4)/100=43/100=0,43
5/6-3/8=(5*4-3*3)/24=11/24
4356+(у-675)=5893
<span>4356 + у - 675 = 5893
у + 3681 = 5893
у = 5893 - 3681
<em><u> у = 2212</u></em>
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4356 + (2212 - 675) = 5893
4356 + 1537 = 5893
5893 = 5893
</span>