# Guess the word with the hints

I have perfectly aligned teeth. Mind you at times I have many.
I do not bite. Aren't you surprised what do I do with so many?
I'm best when I'm like a teenager's face.
You do something to me and I multiply/divide the effect.
Without my brothers and sisters I'm almost useless.

What am I?

## 2 Answers

I'd say you're a

Gear.

I have perfectly aligned teeth. Mind you at times I have many.

I do not bite. Aren't you surprised what do I do with so many?

Gears have teeth

I'm best when I'm like a teenager's face.

Gears are best to be greasy like a teenager's face

You do something to me and I multiply/divide the effect.

Gears multiply/divide the power transfered through them

Without my brothers and sisters I'm almost useless

Only one gear isn't very useful without another

• aaaah! i think you beat me by a minute... well good job to you! Commented Oct 7, 2016 at 7:14
• @stackreader by a minute... or 4 hahah good job anyway Commented Oct 7, 2016 at 7:16
• @lois6b or 5 :P Commented Oct 7, 2016 at 7:16
• Damn. That was quick. I actually thought that it would take people time to get to the answer. Commented Oct 7, 2016 at 7:27

You are a

gear!
adding or removing gears in set multiply or reduce the effect.
but a gear by itself is useless
it has many teeth, but useless if not greasy ;P

EDIT

I'm not sure how a gear work to tell the truth, so not sure about the multiply part. I just assumed it somehow worked like pulleys.

• A small one multiplies the rotation of a big one. Commented Oct 7, 2016 at 7:20
• So the torque increase but required input power is the same? Commented Oct 7, 2016 at 7:22
• Say you have a big gear and a small gear. If the big gear rotates once, the small gear that is connected to it will rotate more than once because it has a greater circumference. So people attach smaller gears to big gear placed in axles to rotate stuff using lesser energy. Now if you rotate the small gear once, the big gear will not even complete one rotation. Commented Oct 7, 2016 at 7:25
• You weren't the first to answer so am not choosing your answer as the accepted answer. You deserve an upvote :) Commented Oct 7, 2016 at 10:01