Step by step
The question
Question: 5 more than twice a number is 17.
Find the number.
1 Find what we know
What do we know?
5 more than twice a number is 17.
What do we want?
The number.
2 Name the unknown
We don't know the number.
So we call it x.
3 Write the equation
Change the words to math, one part at a time.
We start with twice a number, then add 5.
So the equation is 2x + 5 = 17.
Now we solve it.
We want x by itself.
Two things are stuck to x: times 2 and + 5.
The + 5 is on the outside, so it comes off first.
Then the times 2.
4 Remove the + 5
To remove + 5, we take away 5.
We do it on both sides, so they stay equal.
+ 5 and − 5 make zero.
Cross them out.
17 − 5 = 12.
Now we have 2x = 12.
5 Remove the 2
2x means 2 times x.
We want just x.
To remove times 2, we divide by 2.
We do it on both sides, so they stay equal.
2 divided by 2 is 1.
So just x is left.
12 divided by 2 is 6.
So x = 6!
6 Answer the question
The number is 6.
7 Check
Let's check in the story.
Put 6 in the story: 5 more than twice 6.
It makes 17, like the story says.
So the answer is right!
Let's look back.
First: find what we know.
Then: name the unknown.
Then: write the equation.
Then: solve it.
Then: answer the question.
Last: check.