Math Topic Index
Find the Daily Challenge lesson pertaining to any math topic
Acceleration (see Rates)
Accounting,
Arithmetic progression/sequence, M4D5-C1
Arithmetic series, M4D5-C2
Arithmetic tricks, M4D4-C-1
Axes, coordinate M4D14-C1
Binomial, M4D11-Y2
Change of variable, M4D11-Y5
Computer memory storage, M4D1-Y4,
Continued fraction (see Fractions, nested)
Coordinates, M4D15-C1
Decimals,
converting to fractions, M1D1-Ch-1, M1D1-Ch-1, M4D8-C1, M4D8-Y1
non-repeating non-terminating, conversion to fraction, M4D8-C-3
repeating, M1D1-C2, M1D8-Y1, M1D8-Y2, M4D8-C2
0.111..., M1D9-Y2
Denominator (see Fractions)
Difference of squares, M2D7-C4, M4D1-C1, M4D6-C3, M4D6-Y1
Dimensions of a box, M1D6-C1
Distance from point to a line, M4D14-Y1
Distance (see Rates)
Distributive Law, M5D5-C2
Dividing by Zero, M5D13-Y3
Equations, M1D6-C2
in geometry problems, M2D10-Y2
integer equations, M5D13-C1, M5D13-Y
of a line (see Line)
quadratic, M4D11-C1, M4D11-Y1, M4D12-C1, M4D12-Y1
factoring method, M4D11-C1, M4D11-Y1
formula, M4D12-C1, derivation of, M4D12-Y1
Loh Method of Solving, M4D12-C4
rate equations, M1D13-C2, M1D13-Y3
rational, M1D2-C2, M1D4-C2, M1D15-C3, M4D4-Y1, M4D9-Y1
systems of equations, M4D9-C2, M4D10-C1
Expanding, M4D1-Y2, M4D2-Y3, M4D6-C-1, M4D11-C2, M4D11-Y2, M4D16-C1
Exponents,
dividing, M4D7-C3
fractional, M4D7-C2
order of operations, M4D7-C1
powers of 2, 1024⁴, M4D1-Y1
powers of 2, sum of, M4D5-Y-1
powers of 5, M1W2D5-Ch-3
power tower, M4D7-Y1, M5D14-Ch-1
rules for, M4D7-C1
Fermi estimate, M1W3D10-Y-1
Factoring a quadratic, M4D11-C2
Fibonacci Sequence, M4D4-C1
Floor function, M5W2D6-Ch-1
Fractions,
common denominator, M1D1-Y2, M1D4-Y1, M1D13-Y4, M5D5-Y2
continued fraction (see nested)
conversion to decimals, M1D1-Y1, M4D4-Y1, M4D4-Y3
difference of, M0D14-C1
distributions, M1D12-C2
equal to terminating decimals, M5D16-C1
improper, M1D3-Y
in word problems, M1D2-Y1
nested, M1D2-C1
multiplying, M1D1-C3
rationalizing the denominator, M2D2-C4, M2D13-C3, M4D6-C3
reciprocals, M1D15-C3
subtracting, M1D5-Y
Function, M4D4-Y1
Geometric sequence, M4D5-Y2, M4D7-Y1
Geometric series, M4D5-Y2, M4D8-Y1
Geometric mean, M4D7-Y2, derivation of, M4D7-Y3
Graphs, M4D13-C1
continuous, speed and time, M1D16-Y1
bar graph, M1D16-C3
Inequalities,
and geometry, M2D15-Y1
Infinite descent, M5D16-Y3
Intercept of a line, M4D13-Y1
Intersection point using geometry, M4D14-C1
Inverse function, M4D4-Y1
Irrational numbers, M1D2-C4
Limit, M4D16-C3
Line,
equation of, M4D14-C2
midpoint of, M4D13-C6
perpendicular, M4D14-Y2, bisector, M4D13-Y1
Loh method (see Quadratics)
Magic square, M0W2D5
Means (average), M0D5-C1, M3D13-C2, M4D5-C2
sports averages, M1D3-C4, M1D4-C1
geometric, M1D6-C4, M4D7-Y2, derivation, M4D7-Y3
Mental math, M4D2-Y1
Midpoint of a line, M4D13-C6
Multiplying
by 11, M1D3-C2
Parabola, M4D16-C2
converting to decimal, M1D7-C2, M4D1-C1
converting to fraction, M1D8-C1
percent decrease, M1D7-C3
percent increase, M1D7-C1
successive changes in, M1D7-Y, M1D8-C, M4D1-C2
Pi, π, approximation for, M1D3-Y, M1D10-C-3, F254
Polynomials, M4D10-C1
Powers or Power Tower (see Exponents or Number Theory)
Proof of √2 irrational, M5D16-Y4
Proof techniques, M5D16-Y
Proportion (see Ratio/Proportion)
Quadratic equations (see Equations)
Rates, M1D5-Y
acceleration, M1D16-Y2
around a lap, M1D15-Y1
average speed, M1D15-C2
changing rates, M1D16-C1
distance and time, M0D9-C2, M1D15-C1
distance as area under speed curve, F269
distributions, M1D12-C1
relative, M0D9-C1
diagrams for, M0D9-C2
of rotation, M1D11-C1
unit rates, M1D13-C1, M1D15-Y2
speed of rotation, M1D11-C2
Rational expressions, M4D3-C1, M4D3-Y2, M4D4-Y1, M4D11-Y3
Rationalizing the denominator (see Fractions)
Reciprocals, M4D3-Y2
Ratio / Proportion, M1D5-C1, M1D6-Y1, M1D12-Y
of gear speeds, M1D11-C2
Roots,
square root of 2, approximation, M1D2-C4
complex/imaginary, M4D12-Y1
cube roots, M4D7-C1
of a quadratic, M4D11-C3
sixth roots, M4D7-C1
Round down function, M5D6-C1
Scientific Notation, M1D9-Y2, M1D10-C1
Sequences (see Arithmetic Progression)
Simplifying,
shortcuts, M1D10-Y3
radicals, M2D1-C2, M4D7-Y3, M2D13-C3, M2D13-Y2
Slope-intercept form of a line, M4D13-Y-5
Slope,
of a curved line, M4D16-C3
of a line, M4D13-Y3, M4D15-Y1, , F519,
perpendicular, M4D13-Y4
Solutions (see Roots)
Square Root (see Root)
Squaring Numbers Ending in 5, M4D1-C4
Sum of consecutive numbers, M0D5-C1, M0D5-Y1, M1D16-C2
Systems of equations
with two variables, M4D9-C1
with three variables, M0D2-C2, M0D2-Y1, M4D10-C1
in proof of Heron's, M2D16-B2
with too many variables, M5D13-C1
adding/subtracting, M4D10-C4
Telescoping Sum, M0D14-C1
Triangular Numbers, M3D13-C2
Units, M1D13-Y
canceling, M1D10-Y2
Word problem, M4D2-C1, M4D6-Y1, M4D9-C1, M4D12-C1, M4D12-Y1, M4D13-C1, M5D13-C1
Variables, M1D4-C2
Arrangements, increasing and decreasing M3D13-Y1
Beads,
on a necklace, M3D5-Y
Binomial coefficients, M3D6-C1, M5D6-Y
formula for, M3D6-C2
Bounding Boxes, M3D4-C2
Breadth-First Search, M3D15-C3
Casework, M3D5-C2, M3D8-C1, M3D10-C1, M3D10-Y2, M3D11-C1, M3D12-C3
counting angles, M2D8-C3
squares on a grid, M3D4-C1
counting triangles using Triangle Inequality, M2D15-C1, M2D15-Y1
Chess tournament pairings, M3D14-C1
Choose notation, M0D8-C2, M0D8-Y2, M3D5-C2
Choosing
5 choose n, M3D5-C4
9 choose 3, M3D4-Y5
11 choose 2, M3D8-C3
a subset of n things, M0D8-C1, M3D2-C2
toppings for a hamburger, M3D2-C2
Complementary counting, M0D3-C3, M0D3-Y1, M3D4-Y5, M3D8-Y, M3D9-C3, M3D9-Y2, M3D12-C5, M3D12-Y3, M6D1C1
Counting
arrangements in a line, M0D4-Y1
circular arrangements, M0D4-C1
complementary, see Complementary counting
numbers with repeated digits, M0D3-C1
rectangles on a grid, M0D8-Y1
triangles on a grid, M3D4-Y
with lists, M0D3-C1
Depth-Breadth Search, M3D15-Y2
Double factorial, !!, M3D14-C4
Euler's Polyhedral Formula, M3D16-C2
Factorials, M3D1-C2, M3D5-C1, M5D6-C1
Fibonacci Numbers, M4D4-C
and relationship to paths in a grid, M0D15-C2
and relationship to tiling, M3D10-C2, M3D10-C3
GCD of, M5D8-Y
Graph of States, M3D15-C2
Graphs, M3D12-C1
Graph theory, M3D12-C4
Greatest Common Denominator, M5D7-C1
Grid,
representation of ways, M2D15-C2, M2D15-Y1
counting squares on, M3D4-C1
Hockey Stick Identity, M3D6-Y, M3D13-C2, M3D13-C3, F383
Left-Hand Hockey Stick, F477
Inclusion-Exclusion Principle, M3D3-C3, M5D12-Y1, M6D1C1, M6D3C1
Least Common Multiple, M5D7-C1
Line arrangements, M3D1-C
List, ordered, M3D1-C1
Map colorings, M3D12-C1, M3D12-Y1
Matchings, M3D14-C
Multiplication Principle, M0D3-C3, M0D12-C4, M3D13-Y2, M6D1C1
Order, M3D14-C2
Overcounting, M0D8-C3, M3D2-Y, M3D3-C4, M3D14-C1
Pascal's Triangle, M0D15-Y2, M3D6-C2
patterns in, M3D7-C2
sum of row of, M3D7-C3
Paths,
in a hexagonal grid, M0D15-C1
in a square grid, M0D15-Y3, M3D9-C1, M3D9-Y1
Permutations, M0D8-C2, M3D1-C2, M3D5-C, M3D5-Y, M3D14-C1
with repeated objects, M3D5-C1, M3D9-C2
Pigeonhole Principle, M3D12-C3
Pirates splitting gold, M3D8-Y1
Platonic Solid, M3D16-C2
Pouring Buckets, M3D15-C, M3D15-Y
Powers
of 5, M5D6-C3
of 11, M3D7-Y1
Product of GCD and LCM, M5D7-C1
Quotient of LCM and GCD, M5D7-Y
Recursion, M0D15-C2, M3D10-C3, M3D10-Y3, M3D11-C2, M3D11-Y2, M3D14-Y2
Recursive formula, M3D10-Y3, M3D14-Y2
Seating arrangement, M3D14-Y1
Set notation, M3D3-C1
Sets,
intersection of, M3D3-C1, M3D3-C2
Stars and bars, M3D8-C2, M3D8-Y, M3D13-C3
Symmetry, M0D4-C2, M3D1-Y2, M3D9-Y2, M6D2C1
rotational, M3D5-Y2
Tiling, M3D11-C4, M3D11-Y3, M3D14-Y2
tiling a strip, M3D10-C1, M3D10-Y1
Tree Diagram, M0D3-C2, M0D8-C3, M3D1-C3, M3D1-Y1, M6D2C1
Venn Diagram, M3D2-C, M3D2-Y, M3D3-C, M3D3-Y, M5D9-C5, M5W3D12-Y-1, M6D3C1
Altitude,
dropping an, M2D4-Y2
Angle chasing, M2D5-Y2, M2D13-C2
Angle Bisector,
line, M2D12-C1
Theorem, applications of, M2D13-Y2
Theorem, proof of, M2D13-C4,
Angles,
alternate interior angles, M0D13-C1, M2D2-Y1, M2D5-C2
between chord and radius, M2D7-C1
central angles of a circle, M2D6-C2,
complementary angles, M2D5-Y2
corresponding, M2D2-Y1
exterior angle of a non-regular polygon, M0D13-C4
exterior angle of a regular polygon, M2D1-C1, M0D10-Y2
Sum of, M0D13-C5, M2D1-C1 ,
octagon, M2D2-C1
in a line, M0D13-C2
inscribed in a circle, M2D6-C3, M2D8-C1, ,
Interior angle of a regular polygon, M2D1-C1, M0D13-Y
sum of angles in a pentagon, M0D13-C3
sum of angles of a triangle, proof, M0D13-C1
supplementary angles, M2D8-C3
Arc measure, M2D6-C4, M2D8-C1, M2D10-Y1
Arcs,
inscribed, M2D10-C1
Area,
difference of areas, M2D3-Y2
of a circle, F212
of a crescent (lune), M2D3-Y1
of a half-almond, M2D3-C2
of a parallelogram, M2D4-C1
of a trapezoid, M2D4-Y3
of a triangle, M0D1-C1, M0D1-Y1, M2D4-C2, M2D13-C1,
Heron's Formula, M2D16-C2,
of a wedge, M2D3-C3
Chords
intersecting in a circle, M2D6-Y2
angles of, M2D7-C2
intersecting a diameter, M2D7-C4
common chords between circles, M2D7-Y1, M2D16-Y
common chord endpoints lie on a circle, M2D7-Y2
of concentric circles, M2D9-C1
Circles
circumference, M0D10-C1, M0D10-Y1, M1D11-Y1
concentric, M2D9-C1
inscribed in a quadrilateral, M2D12-C2
inscribed in a triangle, M2D13-Y1
pi, M0D10-C1, approximations for, M0D10-C4
overlapping, area of, M2D3-C1
tangent circles, M2D9-Y1
Congruent
example of, triangles, M2D9-C3, M2D13-C1
Coordinates, graphing, M4D13-C1
Cyclic quadrilateral, M2D8-C1, M2D1-Y1
opposite angles of, M2D8-C2
proving it is, M2D8-C4
Distance,
between point and line, M4D14-Y1
Edges of a 3-D shape, M3D16-C1
Euler's Polyhedral Formula, M3D16-C3, M3D16-Y2
Extending Lines in a Figure, M2D1-Y1, M2D4-C3
Exterior Angles (see Angles)
Exterior Angle Theorem, M2D6-C2
Faces of a 3-D shape, M3D16-C1
Heron's Formula for area of a triangle, M2D16-C2, M2D16-Bonus
proof of, M2W4D16-B
Icosahedron, M3D16-C2
Inscribed
circle in a quadrilateral, M2D12-C2
sum of opposite sides, M2D12-C2, M2D12-C3
circle in a triangle, M2D13-Y1
Kites, M2D5-Y1, M2D10-Y1, M2D12-C1, M4D15-C1,
Lines,
sliding lines over, M2D11-C1, M2D11-Y-2
Parallel lines,
cut by a transversal, M2D2-Y1
Paralellogram,
diagonals of, creating four equal-area triangles, F284
Paths,
shortest path on a cube, M2D14-Y1
Platonic Solid, M3D16-C2
Polyhedron, M3D16-C2
Power of a Point, M2D7-C3, M2D7-Y1
for a point outside the circle, M2D8-Y2
Pythagorean Theorem, M0D1-Y2
derivation of, M0D1-C2, M0D1-C4
applications of, M2D1-Y2, M2D1-Y2, M2D2-C3, M2D7-C1, M2D11-Y2, M2D11-C2, M2D14-C3
in proof of Heron's, M2D16-B2
Pythagorean triples, M2D16-C1
Quadrilateral
tangential, M2D12-C1
proof of sum of opposite sides, M2D12-C3
area of, M2D12-Y1
Radii, M2D6-C1
Reflections
of a path in a rectangle, M2D14-C1
Scaling,
of areas, M0D6-C1, M0D6-Y2, M2D3-Y3
of volume, M0D6-C3
with triangles, M2D1-C3, F203,
Secant lines
from an exterior point to a circle, M2D6-Y1, M2W2D8-Y-1
Secant-tangent lines from exterior point to a circle, M2D8-Y2, M2D10-C2
Semi-perimeter, M2D16-C2, M2D16-B1
Similar shapes
similar triangles, M2D1-C3, M2D5-C2, M2D7-C2, M2D8-Y1, M2D11-Y1, M2D13-C1, M2D14-C3, M4D13-C1
similar triangles from dropping altitude, F138, F274
used to find intersection of lines, M4D14-C1
Stellated Dodecahedron, M3D16-Y1
Tangent to a curve, M4D16-Y1
Tangent to a circle
equal length tangents to a circle, M2D12-C1
inner tangent to circles, M2D11-Y1, M2D11-Y2
perpendicular to radius, M2D11-Y1
proof of, M2D9-C2
tangent to two tangent circles, M2D11-C1
Tangent-tangent inscribed angles, M2D10-Y1
Trapezoid,
diagonal length, M2D5-C1
isosceles trapezoid, M2D4-Y1
right trapezoid, M2D5-C1
Triangle Inequality, M2D14-C2, M2D15-C2, M2D15-Y1,
proof of, M2D15-C1
Triangles
3-4-5 triangle, M2D1-C1
3-5-7 triangle, M2D1-Y1
30°-60°-90° triangle, M2D1-C4
45°-45°-90° triangle, M2D2-C3, M2D2-Y2
5-12-13 triangle, M0D1-Y1, M2D11-C2
8-15-17 triangle, M2D5-C4, M2D7-C1
9-40-41 triangle, M0D1-Y1
13-14-15- triangle, M2D16-C1
equilateral, M2D1-C1
area of, M2D1-C2
formed from circle intersections, M2D3-C1
from centers of tangent circles, M2D9-Y2
golden, M2D13-C1
isosceles, M2D6-C1
Unfolding, technique for finding shortest paths, M2D14-Y1
Vertices of a 3-D shape, M3D16-C1
Volume
of a box, M0D2-C1
of a sphere, M0D6-C1
Bases,
Chinese Remainder Theorem, M5D10-C1, M5D10-Y1
Congruence, M5D11-C1, M5D12-C1
Congruent numbers, M5D1-C1
Divisibility, M3D3-Y1
by 3, M5D2-Y1
by 4, M5D3-C4
by 7, M5D15-Y3
by 8, M5D3-Y1
by 9, M5D2-C1
by 12, M5D3-C1
Euclidean Algorithm, M5D8-C1
Euler's Totient Function, M5D9-C6, M5D9-Y1, M5D12-Y1
Factors, M0D2-C1, M0D12-C1, M5D4-C1
average of, M5D5-C1
prime, M0D7-C1
reciprocals of factors, M5D5-Y1
sum of, M5D5-C2
of 11, M5D4-C2
Integer equations, M4W2D6-Ch, M4W2D6-Y
Last digit
of a square, M5W1D1-Ch-1
of a power tower, M5W4D14-Ch-1
Least Common Multiple, M0W2D7-Ch-2
Mod notation, M5W1D1-Ch-4
numbers mod 10, M5W1D1-Ch-5
mod 11, M5W1D1-Y-1
Modular multiplication, M5W1D1-Ch-6
Modulus, M5W1D1-Ch-4, M5W3D10-Y
Multiplicative inverse, M5W4D15-Ch-4, M5W4D15-Y
Palindromes, M5W1D4-Ch-1
Powers
of 5, M5W2D6-Ch-3
of 11, M3W2D7-Y-1
Prime factorization, M0W1D2-Ch-2, M0W2D7-Ch-3, M0W3D12-Ch-4, M5W2D5-Ch-1
of 1001, M0W1D2-Ch-2, M1W2D7-Ch-4, M1W3D11-Y-3
of 111, M1W4D13-Y-4, M4W2D8-Ch-1
Prime numbers, M0W3D12-Ch-2, M5W2D5-Ch-1
Proof of √2 irrational, M5W4D16-Y-4
Relatively prime, M5W3D9-Ch-4, M5W3D12-Ch-3
pairwise relatively prime, M5W3D12-Ch-3
Remainders, M0W4D16-Y
cycles of, M5W3D9-Ch-3, M5W3D10-Ch-4, M5W3D11-Ch-3
mod 2, M5W1D3-Ch-3
of any power, M5W4D14-Y
of powers of 7, M5W4D14-Ch-2
mod 99, M5W1D4-Y-1
of Square Numbers, M0W4D16-Ch-1
negative, M5W1D1-Ch-7, M5W1D1-Y-2, M5W1D3-Y-3, M5W1D4-Ch-4
table of, M5W3D9-Ch, M5W3D10-Ch, M5W3D11-Ch-2, M5W3D12-Ch-3, M5W4D14-Y-2, M5W4D15-Ch-1
Simon's Favorite Factoring Trick, M5W4D13-Ch-2, M5W4D13-Y
Square numbers, M0W3D12-Ch-3