I'm not quite sure if this is what you mean but:
9/9=1
9+1=10
9/9=1
10*1=10
The whole thing:
(9/9)*(9+(9/9))=10
(99)/(99) +9.
Five 9s:(99 x 9 + 9) / 9 = 100
9 + (9/9) = 10
It is five.
9 + (9/9) = 10(99/9) - (9/9) = 10
Ninety nine divided by nine equals eleven
Yes, there are an infinite number of posibilities. Staying only with positive odd numbers, if duplicates are allowed, then five 9s and five 11s make 100. If duplicates are disallowed, then 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 = 100
10 times
wait not the discription srry
1*10**-9s
90 / 9 = 10
1 ns (nanosecond) = 10-9s 1s / 10-9s = 109 109 = 1000 000 000 1 second = 1000 000 000 ns (nanosecond)