ADDITION AND SUBTRACTION
The Scratch Algorithm for Addition
Addition in Bases other than Base-10
Making an Addition Table for a Base other than Base-10
Closure Properties, more examples
MULTIPLICATION AND DIVISION
Lattice Multiplication
Multiplication in Bases other than Base-10
Long Division - dividing by a 1-digit number
Long Division - dividing by a 2-digit number
MENTAL MATHEMATICS AND ESTIMATION
DIVISIBILITY
Divisibility and Divisibility Theorems
Rules for Divisibility by 2, 4, 8, 5, and 10
Rules for Divisibility by 3, 6, 9, and 12
Rules for Divisibility by 7 and 11
PRIME AND COMPOSITE NUMBERS
Determining Whether a Number is Prime or Composite
GREATEST COMMON DIVISOR AND LEAST COMMON MULTIPLE
Finding the Greatest Common Divisor
The Euclidean Algorithm for Finding the Greatest Common Divisor
Finding the Least Common Multiple
Finding the Least Common Multiple of 3 or more Numbers
The Greatest Common Factor - Least Common Multiple Product Theorem