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Mathematics: explore STEM content (page 13 of 23) · openstem
Explore STEM Content
Search the community's STEM library — free to study, yours to make your own.
Mathematics
Algebra, calculus, proofs and statistics on openstem — flashcards, notes, quizzes and plots shared by the community. Study free, or clone anything into your library.
Doubling Doubling makes a number twice as big. The easy way is to add it to itself: double 4 is 4 + 4 = 8. A doubles fact is just an addition where both numbers match, like 6 + 6. Learn 6 + 6 = 12 and you've learned double 6 as well; they'r
Pairs that make a target A number bond is two numbers that add to make a target. Learning the bonds to 10 and 20 by heart makes everything else faster, because you stop counting and start remembering. Each bond works both ways round: 7 + 3
Rational: it can be written as a fraction That includes whole numbers (5 = 5/1), ordinary fractions (3/4), and negatives (−2/3). In decimal form a rational number always does one of exactly two things: Irrational: it can't An irrational num
Two things happening together You can already find the chance of one event, like rolling a 3. A compound event asks about two or more together: flip a coin AND roll a die. To handle that you first need to count every possible combination. T
Population versus sample All of statistical inference is one move: use what the sample tells you to say something responsible about the population you couldn't measure. Why not just ask everyone? Random versus biased In a random sample ever
What does i² equal, and why does that rule matter for complex numbers?1 / 8
i² = −1. Every time a product of two complex numbers produces an i² term, that rule is what lets you turn it into a real number — it is the single fact that makes all complex arithmetic work.