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### Course: Early math review>Unit 4

Lesson 3: Equal sign

# Equal sign

Learn what the equals sign means.

## Want to join the conversation?

• I have noticed that any math problem I do, will most likely always have an equal sign. So, I would like to know, does every math problem have an equal sign?
• Not all problems have equal signs. There are things called order of operations where you can't use an equal sign I believe
• I don't get it it's using the symbol = and 81 isn't equal to 18 so why did he use the equal sign?
• That is just an example of something that is false: 18 = 81 is not true (as opposed to say 24 = 2 + 2 being true).
You can use the 'not equal' sign here: 18 ≠ 81, as 18 is not equal to 81
• at he says that 5 = 3+2 is the same as 3+2=5
how does that work?
i mean, there's a commutative property for mult and adding
but an equal sign?
• You have written the answer in your question. Because of the Commutative Property of Addition, 5 = 2 + 3 and 3 + 2 = 5. They both equal the same amount.
• Who came up with the equals sign and when?
• It was invented in 1557 by Robert Recorde. Rober Recorde was a Welsh physician and politician. He also introduced the plus sign to English speakers in 1557 as well.
• what does = mean with a line over it /
• I believe you are referring to the ≠ symbol, which means "not equal."

For example, I could write 2 + 3 ≠ 4.
• Is there a sign for things that are unequal on a computer (eg 1 doesn't equal 3)?