Branch 03 · free, no sign-up
Basic Math Calculators
The basic math calculators everything else is built on. If a later topic keeps going wrong the cause is usually here, and it is usually the order of operations.
Every calculator in this branch is checked by a mathematician before it goes live.
- √72 the expression
- √(36 · 2) split off the largest square factor
- 6√2 √36 = 6, and 2 has no square factor left
Calculators
All 16 basic math calculators, by topic
the operations, then what you build from them
Arithmetic
Roots & Powers
Factors & Multiples
Percent & Value
Where this sits
What comes before basic math
each topic assumes the one to its left
Stuck part way through? Start at the leftmost topic you are not sure about — everything to the right depends on it.
Knowledge base
Read the reasoning, not just the answer
one article per question a teacher would answer
Questions
Asked often enough to answer here
the ones that change how you work, not trivia
Does PEMDAS mean multiplication always comes before division?
No, and this is the most common misreading. Multiplication and division rank equally and are done left to right, as are addition and subtraction. The acronym pairs them for pronunciation, not for priority.
Why is the square root of a negative number not allowed?
Not in the real numbers, because no real number squared gives a negative result. It becomes possible once you meet imaginary numbers, which is where i = √−1 comes from.
What is 0!?
One. It looks arbitrary, but it is the only value that keeps the pattern n! = n × (n−1)! working all the way down.
Nearby
Branches that touch this one
linked because the maths overlaps, not because it fills space