Here it is step by step:
The sum of 8 and a certain number is equal to the product of the number and 3.
Replace the words "a certain number" and "the number" by N. Then
the sentence becomes:
The sum of 8 and N is equal to the product of N and 3.
Replace the words "The sum of 8 and N" by 8+N. Then
the sentence becomes:
8+N is equal to the product of N and 3.
Replace the words " the product of N and 3" by N×3. Then
the sentence becomes:
8+N is equal to N×3.
Replace the words "is equal to" by the symbol =, an equal sign.
Then the sentence becomes:
8+N = N×3
To avoid the × sign for multiplication we use the commutative principle
and replace N×3 by 3N. Then the sentence becomes:
8+N = 3N
Then we subtract N from both sides and get
8 = 2N
Then we divide both sides by 2 and get:
4 = N
So the number is 4.
Edwin
