Calculate the percentage by mass of all the conponent elements in calcium trioxo carbonate (iv) (ca=40, c=12,0=16? What is the answer of this question?

Answer 1

CaCO3 has mass 100
so now take the total mass of Ca, C, O and divide by 100 to get the %

Answer 2

oobleck omitted a step.
"so now take the total mass of Ca, C, O and divide by 100 to get the %" and it should be
so now take the total mass of Ca, C, O and divide by 100 to get the fraction, then multiply by 100 to convert to %.