its a math question

Question

Zombies lose limbs. Mutants grow limbs. Mutant-zombies do both. Today, a certain mutant-zombie grew 55 limbs, lost 1212 limbs, and grew another 22 limbs.

How many limbs does the mutant-zombie have compared to yesterday?

Answer 1

Since I'm a little more beginner than Irene R. above, I went about this a different way. It's less mathematically "official" and a little more off beat. It would probably work for someone who is a few levels below the person who posted the question.

The prompt is tricky because at first you might think, oh no, we have to worry about three types of creatures: zombies, mutants, AND mutant zombies! But then, upon further reading, we can see that we don't need to worry about what zombies or mutants do-- only what Mutant Zombies do! (Why? Because in order to figure out how many limbs the mutant zombie has the next day, we only need to know how many he/she lost and how many he/she gained. We don't need to bother with what mutants or zombies do; this is a moot point. It doesn't affect the fact that our mutant zombie is simply gaining and losing limbs.)

I'll call the Mutant Zombie MZ.

So, since the order in which the MZ lost and gained his/her limbs doesn't matter, I decided to streamline the losing and the gaining of limbs into two categories: total gains and total losses. Since the MZ lost 1210 limbs, I started the MZ at -1210 limbs. This was just easier for me.

Total gains of limbs? 55 + 22, right?

So MZ who started at -1210 gained 77 limbs. -1210+77 is the equation.

Easiest way for me to solve it was to make it nice clean simple numbers. So I wanted to get to -1200 because that'd be easier for me to do the math this way. To get to -1200, we'd gain 12 limbs. So now MZ is only gaining 65 more limbs. Removing the negative sign to do the math made it so all I had to do was say 1200-65 = 1135. How many limbs were needed to get to 1200 from 65? 1135. Just add the negative sign back in, since the numbers I'm playing with were losses; I was just removing the negative sign to do the arithmetic.

So in short:

-1212

+77

I took 12 from 77 to make the total losses a nice clean 1200, which was easier for me to work with.

Now we have -1200 + 65.

1200-65 = 1135

1135 limbs lost (or, negative 1135 gained)

Hope that was helpful for someone out there, despite it being a little "off the beaten path!"

Answer 2

The situation can be modeled using the following integers: + 55 - 1212 + 22

This is equivalent to losing 1135 limbs (-1135) since yesterday.