Online Course Discussion Forum

Math challenge Number Theory I-B

 
 
Picture of Amber Lin
Math challenge Number Theory I-B
by Amber Lin - Tuesday, 6 August 2019, 3:11 PM
 

I don't know how to solve in Chapter 6:

6.21 and 6.22

 
Picture of David Reynoso
Re: Math challenge Number Theory I-B
by David Reynoso - Wednesday, 7 August 2019, 6:34 PM
 

6:21. Use the fact that $3! = 3 \times 2!$ and $4! = 4 \times 3 \times 2!$ to factor out $2! + 4! + 5!$. You can do something similar with the other one.

6.22: Factor out each of the numbers using prime numbers and look at the prime numbers that were used (along with their exponents). The LCM will be the product of all the distinct prime numbers with the largest exponents you got in the prime factorizations.