Final answer:
To find the sum of two numbers using the GCF and the Distributive Property, first find the GCF and then use the Distributive Property to rewrite the expression. Finally, evaluate the expression to get the sum.
Step-by-step explanation:
To find the sum of 42 and 78 using the GCF and the Distributive Property, we first need to find the greatest common factor (GCF) of the two numbers. The GCF of 42 and 78 is 6. Next, we can use the Distributive Property to rewrite the sum as 6(7 + 13). Finally, we evaluate the expression inside the parentheses to get 6(20), which equals 120. Therefore, 42 + 78 = 120.