Question

Henry was thinking of a number. Henry doubles it and gets an answer of 4. What was the original number?

Answer 1

Let x be the number Henry is thinking of.

The number is doubled and got an answer of 4.

That means:

2 · x = 4

or

2x = 4

This is the equation when Henry doubled the number and got 4 as an answer.

Solve it by dividing both sides by 2.

2x ÷ 2 = 4 ÷ 2

x = 2

The original number Henry was thinking was 2.

Cheers!