Question 84694
Start by making "a number"=x "twelve less"=-12 and "equal" to =

by changing the words into their literal meaning you get the equation

-12+2x=-1

add 12 to each side

-12+2x=-1
+12    +12
________________

2x=11

divide by 2

x=5.5 or 11/2

so your number is 5.5