2,5+4,5=

To add the numbers 2.5 and 4.5, you combine the whole numbers and then the decimal fractions:

2.5 +4.5

7.0 or simply 7

So, 2.5 + 4.5 equals 7. Please note that in some countries, a comma is used as the decimal separator instead of a period. Hence, 2,5 + 4,5 would still equal 7.