Mathematics isn’t always about things being equal. Sometimes we only know that something is greater than or lesser than something else.
We call these things inequalities.
For example, Sue and Jane ran a race.Sue ran farther than Jane.
We don’t know how far they ran, but we know that Sue ran a longer distance than Jane.
We can express that in math terms as follows:
Where x is how far Sue ran, and y is how far Jane ran, and “>” means greater than:
x > y
These are the important signs to know
= When two values are equal we use the ‘equals’ sign
< When one value is smaller than another we use the ‘less than’ sign
> When one value is greater than another we use the ‘greater than’ sign
Why do we use these signs?
We use these signs because, despite the fact that we don’t know exactly how two values relate (such as 2 + 2 = 4), we do still know something about how those two values relate (such as x > y).
Let’s look at an example:
Jane buys her sister a chocolate bar. She hands the cashier $5 and the cashier hands her the change. How much did Jane spend?
So what do we know here?
We know that Jane spends more than $0.
Jane spends > $0
We also know that Jane spends less than $5.
Jane spends < $5
This can be written down as follows:
$0 < Jane spends < $5
We provide some kindergarten worksheets on more than / less than on this page.
Solving inequalities becomes more complicated in algebra. We’ll take a look at that in our next blog post.
