Question

Mental Arithmetic: work the following exercises in your head. Do not calculate with a pencil or paper. Do not use a decimal.

Think of the number eleven.
Now add seven to it.
Now subtract nine.
Now add six.
Now subtract four.
Now add nine.
Your answer is _____

Answer 1

20

Explanation:

`11+7=18\\\\18-9=9\\\\9+6=15\\\\15-4=11\\\\11+9=20`

Answer 2

The answer of this Mental Arithmetic problem is 20.

Explanation:

Think of the number eleven.

11

Now add seven to it.

`11+7=18`

Now subtract nine.

`18-9=9`

Now add six.

`9+6=15`

Now subtract four.

`15-4=11`

Now add nine.

`11+9=20`

Your answer is 20.