Foundational math vocabulary
Number
Pronunciation: NUM-ber
A number tells how many, how much, which position, or which label is being used.
nℕℤℚℝFoundational
Plain language
What it means
A number tells how many, how much, which position, or which label is being used.
Formal meaning
Mathematical definition
A number is an abstract mathematical object used to count, measure, order, or identify.
Where it fits
Its place in mathematics
Number sense is the foundation beneath arithmetic, measurement, algebra, and data.
Why it matters
The practical reason to learn it
Numbers let people compare quantities, record measurements, plan resources, and notice patterns.
Worked example
Compare two numbers
Which is greater: 37 or 42?
- Compare the tens digits: 3 tens and 4 tens.
- Because 4 tens is greater than 3 tens, 42 is farther right on a number line.
42 is greater than 37.
Real-life example
Where this appears
A warehouse worker uses item counts to decide whether an order can be filled.
Common mistake
What to watch for
Treating a numeral such as 12 as the same thing as the quantity it represents. The symbol is the written name; the number is the idea.
Memory tip
Keep this in mind
Ask what the number is doing: counting, measuring, ordering, or labeling.
Little-known fact
Keep curiosity alive
The same number can be written in many forms, including words, numerals, fractions, decimals, and other bases.
A profession that uses this idea
Inventory depends on number sense
Business owners compare stock counts, sales totals, prices, and quantities before making decisions.
Explore Merchants & Business OwnersFollow the learning trail
Prerequisites, related ideas and next concepts
People behind the ideas
Related Math Heroes
Ahmes
An Egyptian scribe whose surviving copy of an older mathematics text preserves arithmetic, fractions, measurement, and practical problem solving from the ancient world.
Liu Hui
Liu Hui was mathematician and commentator. His commentary on The Nine Chapters explained algorithms, justified procedures, and refined approximations to pi.
Put the idea to work