This is a case of conversions. Firstly, we will need to know the amount or number of cubic centimeters in one cubic meter. By conversion, we have 1000 of such.
This practically means before we could form one cubic meter of water, 1000 units of water having a volume of one cubic centimeter each would have come together.
Now, we know that one cubic centimeter has a mass of 1g, this means 1000 cubic centimeter would have a mass of 1000 * 1 = 1000g or 1kg
Hence 1.27 cubic meter of water will thus have a mass of 1.27 * 1000g = 1270g or simply 1.27kg
