Equal, Greater or Less Than
Here is a summary:
| Symbol | Words | Example Use |
|---|---|---|
= | equals | 1 + 1 = 2 |
≠ | not equal to | 1 + 1 = 1 |
> | greater than | 6 > 3 |
< | less than | 5 < 9 |
≥ | greater than or equal to | x ≥ 1 |
≤ | less than or equal to | y ≤ 3 |
To remember which way around they go, just remember BIG>small or small<BIG:
Why would you use these?
Because there are things you do not know exactly, but can still say something about.
Example 1: Paul has $10 and he is going shopping. How much will she spend (without credit)?
Answer: Something greater than, or possibly equal to $0 and less than or possibly equal to $10:
Paul Spends ≥ $0
Paul Spends ≤ $10
This can be written down in just one line
$0 ≤ Paul Spends ≤ $10
(note that "≥" had to be flipped over to "≤" when we put it before what Paul spends - always make sure the small end points to the small value)
Example 2: Paul comes back with something he has bought and says "and I got change". How much did she spend?
Answer: Something greater than $0 and less than $10 (but NOT $0 or $10):
$0 < Paul Spends < $10
Example 3: What is x+3, when you know that x is greater than 1?
If x > 1 , then x+3 > 4
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