###### tags: `OTM 03` `Prime GCF and LCM`
#
Two numbers a and b, their Greatest Common Divisor(Factor) is 21, their Least Common Multiple is 126. What is $a + b$ ?
<font size = 4>
Hint: 1. $GCF \times LCM = Product$
2. $a$ can be writen as $21 \times x$, with x is a prime. $b$ can do the similar thing
</font>
---
{"metaMigratedAt":"2023-06-17T21:57:34.088Z","metaMigratedFrom":"YAML","title":"OTM 03","breaks":true,"description":"Prime, GCF, LCM","slideOptions":"{\"theme\":\"white\"}","contributors":"[{\"id\":\"d8479402-2b3f-4751-92f6-b67f55f4b94f\",\"add\":466,\"del\":0}]"}