Webinars SET A - Grade 5-6 - Sunday@4:30-5:30pm EST - 10 MEETINGS-Recording 5

Video Transcription

Video Summary

The webinar introduces multiples, factors, prime numbers, prime factorization, and divisibility rules for Math Kangaroo level 6–7.<br /><br />Multiples are products of a number and an integer; common multiples are shared by two or more numbers. Factors divide a number without a remainder and can be organized into factor pairs. Prime numbers have exactly two factors, 1 and themselves; composite numbers have additional factors. A factor tree can be used to find a number’s prime factorization.<br /><br />The lesson reviews divisibility shortcuts: even numbers are divisible by 2; a number is divisible by 3 or 9 if its digit sum is; divisibility by 4 depends on the last two digits; divisibility by 5 depends on the final digit being 0 or 5; and divisibility by 8 can be tested using the last three digits. Divisibility by 12 can be checked by testing divisibility by both 3 and 4.<br /><br />Practice problems apply these ideas to counting common multiples, finding the least common multiple, determining prime factors and the number of divisors, and solving logic and digit puzzles. A marble-packing problem illustrates using the greatest common factor to find the largest equal box size, then calculating the total number of boxes.<br /><br />The instructors recommend organizing information, using casework where appropriate, memorizing key prime numbers and divisibility rules, and practicing with past Math Kangaroo contests.

Keywords

multiples

factors

prime numbers

prime factorization

divisibility rules

common multiples

least common multiple

greatest common factor

Math Kangaroo

number theory