Multiples, divisors and primes

Divisibility rules, factorization, GCD and LCM

The Multiples, divisors and primes unit belongs to the Arithmetic and mental math section of Math Mental and has 15 lessons: divisibility rules, factorization, GCD and LCM.

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Sample questions

In the lesson, numbers change every session and the solution appears after you answer.

$3 \mid 3\,741$
Step by step
1. $\displaystyle 3 + 7 + 4 + 1 = 15$
2. $\displaystyle 15 = 3 \cdot 5$
Answer $\checkmark$
$D(18)$

Answer $\{1, 2, 3, 6, 9, 18\}$
$84$
Step by step
1. $\displaystyle 84 = 2 \cdot 42 = 2 \cdot 2 \cdot 21$
Answer $2^2 \cdot 3 \cdot 7$

Lessons in this unit

Divisible by 2, 5 and 10 Lesson, 8 questions
Divisible by 3 and 9 Lesson, 8 questions
Divisible by 4 and 6 Lesson, 8 questions
Practice: divisibility rules Practice, 10 questions
Multiples Lesson, 8 questions
Divisors in pairs Lesson, 8 questions
Primes and composites Lesson, 8 questions
Prime factorization Lesson, 8 questions
Repeated factors Lesson, 8 questions
Practice: primes and divisors Practice, 10 questions
GCD and LCM by listing Lesson, 8 questions
GCD and LCM by factorization Lesson, 8 questions
Euclidean algorithm Lesson, 8 questions
GCD and LCM word problems Lesson, 8 questions
Unit test 12 questions

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Sample questions

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Lessons in this unit

Your first lesson takes five minutes