HCOOH + CaCO3 will give what (what are the products)

Answer 1

The H on the right hand side of HCOOH is the active H (as in HCl etc) and from there it's a usual acid/carbonate reaction.
HCOOH + CaCO3 ==> Ca(HCOO)2 + H2O + CO2
You balance.

Answer 2

CaCO3 + HCOOH = H + CaCOOH + CO3

of course that needs H2 on the right so double everything if writing a balanced equation

Answer 3

Use what Dr Bob said