What is the difference between non-integers and float values?

Question

When practicing Type Conversion this code appeared:
>>> float(input("Enter a number: ")) + float(input("Enter another number: "))
Enter a number: 40
Enter another number: 2
42.0

At the end it specified that if non integers or float numbers are inserted on the code will cause an error, but I tried inserting
Enter a number: 30.2
Enter another number 2 and it came out as
32.2

So what is the rule exactly? Can someone explain the difference?