Question

How do i write 4 less than twice a number as an algebraic expression?

Answer 1

`2n-4`

Explanation:

We'll refer to our number as `n.`

The problem says we have twice the number. This would mean the number is multiplied by two, or `2n.`

Moreover, we want four less than twice the number. This entails subtracting `4` from `2n: 2n-4`

In general, when translating from words into expressions:

"less than" implies subtracting.

"more than" implies adding.

"twice/three times/four times/ `x` times" implies multiplying.

"half of/quarter of/tenth of/ `xth` of" implies dividing.

Answer 2

`2n - 4`

Explanation:

We need to rearrange the word problem a little. When they are saying "4 less than twice a number", that's the same as saying "twice a number minus 4". When you are asking for less than something, that indicates subtraction!

We'll abbreviate number to `n`.

`stackrel(2n)overbrace"twice a number" " " stackrel(-)overbrace"minus" " " stackrel(4)overbrace"4"`

`2n - 4`

Here are some helpful tips:

1. When you see "less than" that means that you are going to put that part at the end of the equation and that it will be subtraction.
2. Abbreviate words into something that you can remember. Number starts with `n`, so that is a good way to remember what it represents.