7.5 grams of butter
1. find how many grams of butter it takes to make 4 pancakes; 8 / 2= 4
2. divide the number of grams by the number you just divided by (2)
3. solve 5 / 2 = 2.5
4. acknowledge 8 + 4 = 12, so do 5 + 2.5 = 7.5
You need 7.5 grams of butter