If you are just looking for any number between you can go from 144.810 to 145.154 and you can get even more number if you add a zero to both number because there are lots more between 145.1550 and 144.8090
However, if you are looking for the number that is equidistant between them - the number in the middle, simply add them together and find the average which will be the number in the middle.
So
(145.155 +144.809)÷ 2 = 144.982
