Answer 1

First:
It's just converted to binary. If you have never seen something like this, you can just run through it:
res = num % 2 + res -> num % 2 is 0, so res is 0
num = Math.floor(num / 2) -> num is 2
num % 2 is still 0, so res is 00
Math.floor(num / 2) -> num is 1
num % 2 is 1, so res is 100
Math.floor(num / 2) is 0, so the loop stops there

Second:
c > b is true, meaning it will be converted to true > a. True converted to a number is one, and 1 > 10 is false.

Answer 2

The first program outputs (1+3+5+7+9)*4=100
The second program outputs (30>20)==1(true) <10==false (0) = 2 (console.log) 🤔🤗