What is abc + def? I don’t understand it at all.

Answer:
" The expression consists of 2 terms , and each term contains 3 factors"
Step-by-step explanation:
Given expression is abc+def
In the term abc has a,b,c are factors and term def has d,e,f are factors
It can be written as abc=(a)(b)(c) and def=(d)(e)(f)
Therefore abc contains are 3 factors and def contains 3 factors
" The expression consists of 2 terms , and each term contains 3 factors"