Mr. Mathemagician asks you to pick any whole number. Add 10. Multiply the result

by 4. Add 200. Divide by 4. Subtract your original number. Mr. Mathemagician says,
“You’re final result is 60!” Explain Mr. Mathemagician’s trick?

1 answer

x =original number

Mathematical operations:

Add 10 :

x + 10

Multiply the result by 4 :

( x + 10 ) * 4

Add 200 :

( x + 10 ) * 4 + 200

Divide by 4 :

[ ( x + 10 ) * 4 + 200 ] / 4

Subtract your original number :

[ ( ( x + 10 ) * 4 + 200 ) / 4] - x

Equation is:

[ ( ( x + 10 ) * 4 + 200 ) / 4 ) ] - x =

= ( x + 10 ) * 4 / 4 + 200 / 4 - x =

x + 10 + 50 - x = 60