Please I just need help on the set up teacher wants a guess and check table.

Thomas is thinking of a number. If he doubles his number and subtraction 27, the results is 407. Of what number is Thomas thinking?

2 answers

So we know that the result of doubling a number and subtracting 27 gives 407. Since your teacher wants a guess and check table, let's just start guessing numbers around the 200 mark, since we know double the number at some point.
no need for guessing, just reverse the steps:

the first thing we did was multiply by 2, then subtract 27 to get 407
So everything done in reverse:

( 407+27) divide by 2
= 434 รท 2
= 217