Answer :

I'm not sure if you used the euro sign accidentally or what but this is how to increase 64 by 70%

divide 64 by 10.
6.40
then multiply it by 7.
44.80
then add 44.8 to your original number. (64)
the answer is:
108.8

If you did put that sign there purposely and if it means something then I don't know if it matters or if this is right.