Step by step
The question
Question: Leo needs at least 200 points.
He gets 15 points for each game.
How many games must he play?
1 Find what we know
What do we know?
At least 200 points.
15 points for each game.
What do we want?
How many games.
2 Name the unknown
We don't know how many games.
So we call it x.
At least 200 points means 200 points or more.
We write ≥ 200 points.
3 Write the inequality
In words: what the games make is at least 200 points.
So the inequality is 15x ≥ 200.
Now we solve it.
4 Remove the 15
15x means 15 times x.
We want just x.
To remove times 15, we divide by 15.
We do it on both sides, so the sign stays true.
15 divided by 15 is 1.
So just x is left.
We can make 200/15 simpler.
It is the same as 40/3.
So x is greater than or equal to 40/3.
5 Show it on a number line
6 Answer the question
That is about 13.33.
Games come in whole numbers.
The smallest whole number from 13.33 up is 14.
So we round up.
Careful!
13.33 rounds to 13 the usual way.
But 13 games are 195 points.
That is not enough.
So we round up.
So at least 14 games.
7 Check
Let's check in the story.
14 games: 210 points.
That is at least 200 points.
But 13 games would be 195 points: not enough.
So 14 is the fewest.
So the answer is right!
Let's look back.
First: find what we know.
Then: name the unknown.
Then: write the inequality.
Then: solve it.
Then: answer the question.
Last: check.