First, we need to add the two numbers on the left side of the equation: 17.2 and 1.56.
17.2 + 1.56 = 18.76
Now we have a new equation: 18.76 - 14.4
To solve this, we need to subtract 14.4 from 18.76:
18.76 - 14.4 = 4.36
Therefore, the solution to the original calculation 17.2 + 1.56 - 14.4 is 4.36.