This problem is from khan academy. (I am a adult, just reviewing for future qualifying test in my free time. So dont worry its not a real test.)

Equation: 2/3b+5=20-b

They say they are adding b to both sides: 2/3b+5+b=20-b+b getting: 5/3b+5=20....not sure how they got 5/3b.

Thanks in advanced. Happy holidays.