Regular Expression. Find integers only

Regular Expression. Find integers only

Find only the integers in a math equation...
5 + 5.5 + 6 / 2.0
I want to find the 5 and the 6 not the 5.5 or the 2.0 To find decimals I
use \d+(.\d{1,})
I've tried \b\d+\b but that finds all the digits