Make is a system that has many data types but due to the nature of how it was designed a number is not one of them. There are interesting posts on this that create a bug like this one I posted:
Bug in average() function when passing in numeric strings
Be very careful when dealing with numbers. It’s not really an oversight — it’s sort of a purposeful implementation because json is totally typeless and as a result everything is a string when data comes out of an api.