What is the electrical charge of a calcium ion that has lost an electron?

A calcium ion already is missing two electrons (in its stable configuration corresponding to the nearest noble gas's electron configuration) from its neutral state as an atom. This means that if it looses a third electron, it now has a charge of +3e. e is NOT the charge of an electron, it is the elementary charge unit.

i dont know but i think it dosent have a charge.

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form