My approach:
I labeled all the empty triangles as different variables a,b,c,d,e,f. Now since 1,4,6,10 have already been labeled, I am trying to make equations so that the sum is equal, however only one small triangle, the middle triangle is common to all and I am not understanding how to get to a single answer, let alone finding the total number of ways.
I am not understanding the proper approach to this question
An approach to this question would be appreciated.