You can put the relevant expression into a hidden value that represents the integer form of the value.
Round a number down to the nearest integer
If you want to round a number down you can use the int() function to cut off the decimal point (i.e. 2.2 -> 2; 2.7 -> 2)
Round a number up to the nearest integer
Use the following calculation to always round a number up (i.e. 2.2 -> 3; 2.7 -> 3)
If( int(#form/value) < #form/value, int(#form/value) + 1, int(#form/value))