Input → Output: Survival Math Made Easy

by Todd Walker

What’s Math got to do with survival?


You’ve probably never used Algebra since graduation, but this math lesson may save your life. Is there homework involved? Yes. But you choose the when, where, and how to do it.

If you hate math but love to survive 100% of the time, this lesson is for you. As a math teacher, I want to introduce you to…

Survival Math Made Easy

First, let’s cover some Survival Math terminology so we’re all on the same page. I promise to keep it simple for all the math-haters. You won’t see any of these…

y = -2x + 13

As students of self-reliance, our learning goal is 100% survivability. Shoot for 95% and your dead. You can’t bring this grade up if you’re not alive in class.

Here’s what’s on our word wall…

Key Word #1: Function

In the non-math world, we describe a function as something that works every time. In mathematics, a relation is a function if the input has only one output.

This works for survival, too. Your input into the Survival Function Machine (see diagram ↓) determines your output.

Function of Survival

Output is dependent upon input. Fire is only achieved with the correct input: air, fuel, and a heat source. Take one element of the input away, air, and you get charred material – not fire. This isn’t a bad thing if your intention is to make char cloth for your next fire.

This is but one example that can be applied to our ultimate output → 100% survivability.

Key Word #2: Relation

In relationships, one item depends on another. There’s a relationship between fuel-heat-air and fire. When these three items combine properly, the output is fire. If fire is not the outcome, what variable caused the wood not to burn? Is the tinder marginal or damp? Is your heat source a ferro rod, flint and steel, match, bow drill ember, or Bic lighter? Do they work in your environment?

Here’s an example of a relation. Let’s say you walk up to a vending machine with 6 buttons labeled 1 through 6. Pressing #1 always spits out a bottle of water; #2 gives you a candy bar; #3 gives you a sports drink; #4, a soda; #5 rolls out an apple; and #6 gives you a soda. The unlabeled buttons are related to a specific product or output. Hankering for an apple, you press #5 to get your fruit. This is a relation.

Here’s another scenario with the same vending machine, same buttons, and same six products. You press button 5 expecting your apple, but instead, you get a candy bar. Some days you get an apple, some days you get the candy bar. This too is a relation. You still get a product/output when you press #5.

Both scenarios describe a relation, but the second one is unreliable. You’re never sure what output you’ll get.

In math, we call a relation that is always consistent a function. In survival, you want to know what you’ll get when you press a button on your Survival Function Machine – 100% of the time.

You press a button and expect to get a certain outcome. When the output is not what you expect, your Survival Function Machine isn’t malfunctioning, the input needs to adjust for variability.

Feed the Survival Function Machine

You’ll only get your desired output (100% survivability) by feeding your Survival Function Machine quality stuff. The only way to input the good stuff is by developing knowledge and skills to use your available resources. Or as we call the process, Doing the Stuff of Self-Reliance.

Practicing fire craft in ideal conditions is necessary to build confidence in this skill. But like I heard Creek Stewart say recently, mother nature makes the rules. You won’t always have dry tinder material and fuel. Mother Nature is the biggest variable you’ll have to contend with. You want to remove as many variables as possible for 100% survivability.

Carrying proper gear (10 piece kit) helps eliminate variables.

Input: Gear

Bomb-proof gear. That’s what you’re after. And no, it doesn’t have to break the bank. Buy/trade/acquire the best gear you can afford. One of my best gear shops are antique stores, yard sales, and flea markets.

Here’s the thing about gear…

Kit items are inanimate objects. Tossing that $300.00 knife into your Survival Function Machine will only produce the desired output if you’ve honed your knife skills.

Gear + skills is a function of 100% survivability.

Begin thinking about, if you haven’t already, the multi-functional uses of each piece of gear in your woodcraft kit, bug out bag, vehicle emergency kit, or get home bag. If a piece of gear has only one use, cull it. This advice does not apply to required medications. However, your 10 piece kit is a multi-functional self-aid kit.

Which brings us to what I consider the most important of all the inputs…

Input: Skills

In a 72 hour wilderness survival setting, 100% survivability is dependent upon one thing… Core Temperature Control. Lacking cover and water, you won’t last long exposed to the elements.

CTC functions

What gear/skills do you need which would enable you to add inputs to the Survival Function Machine to achieve the desired output → Core Temperature Control (CTC)?

CTC Input #1 → Cover

Layered clothing is your most important piece of cover. Next, you’ll need to shelter your body from the elements with either a kit item or landscape material.

There’s no such thing as bad weather, only unsuitable clothing.

Are you willing to risk Mother Nature providing suitable cover resources? An emergency space blanket and a clear painter’s tarp weighs little but offers great return on investment as a cover element in cold weather.


This kit item reduces the variability of Mother Nature.

CTC Input #2 → Fire

Fire. Is. Life. It effects your cover element, disinfects water, offers illumination, signalling ability, cooks food, and adds psychological comfort. Radiating heat to warm your body and shelter in cold conditions is the obvious benefit of developing fire craft skills.

Always carry a field tested method of sure-fire in your kits. There’s no cheating when it comes to emergency fire! Man up, swallow your ego, and flick that Bic on some sure fire starter.

CTC Input #3 → Hydration

The most overlooked use of fire may be disinfecting water via boiling in the winter. Staying hydrated in cold weather is just as important as during July in Georgia. In fact, winter time has a way of dulling our senses to the need to stay fully hydrated. It’s not hot out so we often overlook hydration.

Boiling water is my go-to method of disinfection. That’s one reason I’m pyro-crazy about fire craft!

Homework Assignment

Told you there’d be homework.

Experience is a tough teacher, but she’s unforgettable. You still talk to your friends about the toughest teacher you had in school, right? Experience is the only way to build knowledge and skills which will allow you take advantage of available resources. You may gain some knowledge behind your computer screen, but experience only comes by Doing the Stuff (dirt time homework) consistently.

Here’s a relation that is a function every time:

Dirt Time input-output

Mathematics is the study of relationships in the real world in order to learn how things work. You’re not going to be using algebra in a survival situation. But the input/output concept remains. With the proper input into your Survival Function Machine, 100% survivability is the output.

There’s the bell. Go get dirty!

Keep Doing the Stuff of Self-Reliance,


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Categories: Bushcraft, Camping, Doing the Stuff, Preparedness, Self-reliance, Survival Skills | Tags: , , | 1 Comment

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One thought on “Input → Output: Survival Math Made Easy

  1. Pingback: Input → Output: Survival Math Made Easy | Modern Homesteader

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