K–12 · foundations
Arithmetic
Build speed and accuracy with the operations everything else rests on.
Skills
21 skills in 5 sections — fundamentals first, then more specific topics. Practice each until Mastery Score 100.
A.Number systems & factors8 skills
- A.1 Number ClassesPractice →Name the most specific set for a number: natural, whole, integer, rational, irrational, or real.
- A.2 Even & OddPractice →Decide whether an integer is even or odd.
- A.3 Prime & CompositePractice →Classify small positives as prime or composite (1 is neither).
- A.4 Prime FactorizationPractice →Write a positive integer as a product of primes (powers allowed).
- A.5 Greatest Common FactorPractice →Find the GCF of two positive integers.
- A.6 Least Common MultiplePractice →Find the LCM of two positive integers.
- A.7 Square Roots & IrrationalsPractice →Evaluate roots of perfect squares, or say when a square root is irrational.
- A.8 Comparing NumbersPractice →Compare integers, fractions, and decimals with <, >, or =.
B.Integer operations4 skills
- B.1 Integer AdditionPractice →Add positive and negative integers quickly and correctly.
- B.2 Integer SubtractionPractice →Subtract integers, including signed values.
- B.3 Integer MultiplicationPractice →Multiply integers with attention to signs.
- B.4 Integer DivisionPractice →Divide integers that split evenly.
C.Decimals & rounding3 skills
D.Structure & absolute value4 skills
- D.1 Order of OperationsPractice →Evaluate expressions with parentheses, ×, ÷, +, −.
- D.2 Absolute ValuePractice →Evaluate absolute values of integers.
- D.3 Evaluating PowersPractice →Evaluate small integer powers, including negative bases.
- D.4 Division with RemaindersPractice →Find the remainder when one whole number is divided by another.