50*0.25=12.5
50+12.5=62.5
800:62.5=12.8
Ответ: можно купить 12 ручек.
___1\4______3\4___
_____5\12______11\12
_______7\12_2\3_____
__1\6_1\4_________
16-(+4)=16-4=12
(-1)-(-2)=-1+2=1
(-6.3)-(+0.2)=-6.3-0.2=-6.5
1/3-(-1/6)=1/3+1/6=2/6+1/6=3/6=1/2
0-(-7)=7
-2/5-(-1/10)=-2/5+1/10=-4/10+1/10=-3/10
-7+х=15
х=15+7=22
u-5.6=-7.1
u=-7.1+5.6=-1.5
Х×100=900
х=900:100
х=9
456+х=932
х=932-456
х=476
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