Question

Ce numar adunat cu 7,5 da suma egala cu suma numerelor 1,(1) 2,(2) 3,(3)....8,(8)?

Answer 1

1,(1)=(11-1)/9=10/9
2,(2)=20/9..............8,(8)=80/9
x+7,5=10/9+20/9+30/9+.....+80/9
x+7,5=360/9
x+7,5=40
x=32,5

Answer 2

transformi fractiile zecimale in fractii ordinare asa :
1,(1) = 1 inttreg si 1/9= 10/9
2,(2)= 2 intregi si 2/9=20/9
3,(3)=3 intregi si 3/9 = 30/9
..........................................
8,(8)=8 intregi si 8/9 = 80/9
suma numerelor este (10+20+30+....+80)/9 = 360/9 = 40
a+7,5=40
a=40-7,5
a=32,5