a number decreased by the sum of the number and eight
"A number" and "the number" are reoplaced by a letter, say, N.
So the sentence becomes:
N decreased by the sum of N and eight
We replace the words "the sum of N and eight" by "(N+8)" because
the words "sum of___ and ___" means to add with a plus sign
what's in the blanks. Notice that the parentheses are absolutely
necessary because an entire sum must be "packaged". So we have
this:
N decreased by (N+8)
"Decreased by" means "minus", so we replace the words "decreased
by" by a minus sign. So we have
N - (N+8)
Now we remove the parentheses
N - N - 8
N - N is 0. so the answer is
-8.
Edwin
