Mike was going to sell all of his stamp collection to buy a video game. after selling half of them he changed his mind. he then bought ten more. how many did he start with if he now has 27?

Answser:

34

Step-by-step explanation:

think of it as this:

s-(s/2)+10=27

s symbolizes the amount of stamps mike has, now begin to evaluate, (doing the opposite operations to the solution) subtract the 10 from itself and the 10 from the 27

s-(s/2)+10=27

          -10  -10

           0    17

now you have

s-(s/2)=17  

now just multiply 17 by 2 and you get your answer of 34

cut 138 centimeters off

step-by-step explanation:

250-112 = 138