ECN Forum Forums Code Related Discussion NEC & other Code issues electric cooktop rating

Ran into this in a double wide home. 7.7 KW rated cooktop fed with 10/2romex and a 20A DP breaker.Did calculation came up with 32.83A 7700W divided by 240V=32.8A also did it like this 7000.7W divided by 240V=29.16A. What is the correct way to do this calculation?