I'm writing a story that features a main character that wouldn't have any concept of numbers or units of measurement. I'm having a really hard time being descriptive while avoiding their use, to the point where I've already broken the rule a couple of times.
For example, say my character was 5 feet tall. I could write:

"She came across a large being, which was a giant compared to her."
or
"She came across a large being, which towered 3 times taller than her."
or
"She came across a large being, which loomed over her, an unbelievable 15 feet tall."

I feel like sentence one would fit best for someone who doesn't actually know their numbers. They wouldn't be thinking in multiples or fractions or whatever.
two would make sense for someone who knew math, and three someone who knew measurement units (two and three are pretty interchangeable for someone who knows both)

Given my character knows neither it makes sense to stick with descriptions like sentence one, but I feel like that is going to run into a lot of issues with reader clarity.
"a giant compared to her" could mean someone that is 1 foot taller or 10 feet taller or even more. I can make it clearer with more description but I feel it still lacking when you are trying to give the reader a clear picture in their head. This is especially relevant when combat with said creature is involved. It's easy to get really confused if you have the wrong mental image of one of the combatants.

It feels even worse when trying to work with distances. Saying "She only explored a short distance from her cave" is a lot less clear than "She only explored the area within a mile of her cave." I'm not even sure how to make it any clearer than that. I would use "She only explored the area within 15 minutes walk of her cave" but that's also forbidden, what with numbers and time units. 

I've come to the conclusion I may just need to give up on it. I feel like the third person narration makes it more forgivable to do so, but I wonder what other people think?

Does anyone have any suggestions on this front?

That sounds like a lot of work, but I like the idea and think it's cool that you're working it into the narrative itself and not just the dialogue/monologue.

My main advice would be to use points of reference to add comparison.

Quote:"She came across a large being, which was a giant compared to her."

This sentence is pretty good to start with, but it needs more detail. By adding something like, "Even the top of her head didn't reach his shoulders," the readers are able to get an accurate enough idea of the size difference. From this, the readers are able to guess that the thing is about a foot taller than her, because obviously, if she only came up to its knees, we wouldn't have mentioned the shoulders.

"The creature had to hunch over as it made it's way through the forest. Otherwise, it would have struck its head on the lower branches."

"She took a step forward in order to not seem intimidated, but then had to cran her neck back in order to look it in the eyes, and realized how little her bravado actually meant."

"She started her search at dawn, but by the time she made it back to the cave, the sun had reached it's zenith. She hadn't explored far, but it had still taken her longer than expected."

"She didn't realize how long she had been fishing until the tide started to come back in."

"As the candle burned, the nail eventually fell out and she decided that she had waited long enough."

"The river that had once seemed like such an obstacle could now be waded across. The water still came up to her waist, but the current was weakened enough that it no longer threatened to sweep her away."

Just remember that you don't need to give anything an exact measurement. You just need to give them an accurate enough point of reference that their imagination can fill in the blanks.

I have no idea how your idea will turn out in your fiction, but at the very least, it's a good writing exercise. It'll force you to add detailed descriptions to scenes and think of new ways to express ideas. Not all of the little experiments I've tried in my own fiction have ended up working, but I don't regret trying them.

Best of luck.

Thanks! Those are good ideas. I'll try to stick with it for longer. I just need to step up my description game :P

You do get a lot of leeway unless "she" is the one narrating. A semi-omniscient or omniscient narrator doesn't have to hold to your/"her" rules. You do have to be careful about when you are using "her" voice, even if it is by narrator proxy. You still want to err on the side of descriptive for sure. 

The other thing is that the measurements are the author's notes. This is very much a 'show vs tell'. When you say it is 15ft, you are telling the reader that it is 15ft. The most common solution will be to use her voice to put it in perspective. "She looked up, then up, then up again." If you need a soft kind of tell for it to make sense, something like  "It towered over her, larger than the watch tower at home." is enough. The same goes for the 'patrolling'. "She circled her camp to gain the lay of the land; far enough to flee in any direction safely,  deep enough to know where to engage if she had to, and barely enough to know it was safe for now." 

There are lots of ways to show. eg: Tall enough to cast shadows at noon, she stared straight ahead at the beast's knees, "... now I know how a mouse feels"... Bad examples, I'm sure! I'm not very good at it, hah. But the idea is that you are capturing relevance, not just being clinically descriptive.

Quote:The other thing is that the measurements are the author's notes. This is very much a 'show vs tell'. When you say it is 15ft, you are telling the reader that it is 15ft.

Agreeing with this.


When I see an author write something like, "It was 10 meters across," unless it's a slow paced scene, my first thought is going to be, "When did they have time to break out the measuring tape?!"

Even for a regular novel, exact measurements shouldn't be given unless the characters themselves are paying attention to the math.

This sounds like a nice feature. I agree that using exact numbers in the narration should be avoided. Besides, if you write in close third person perspective, then saying something the character has no way of knowing can break the immersion.
Using comparisons to things the readers know is probably the simplest method, like saying the character stands as high as a certain animal or whatever. But an idea I'd have is that maybe she figures out some way to measure distance or time for herself. I don't know how applicable this is, but she could for example use candles and watch how they burn down, then think about how the trip takes as long as a candle. Or maybe following the movement of the sun or even the stars. That's pretty vague, but it would at least tell the readers that she wasn't walking for hours if she says the position of the sun hasn't changed noticeably. Stuff like that.

A lot of great ideas here, and Bizmatech nailed a lot of what I was thinking of writing as I read their comment. 

If you're looking to keep your sample sentence simple, I think the first one can still be expanded upon with a little flavor text.

"She came across a large being, which was a giant compared to her." >>>>> "She craned her neck, squinting in the sunlight, in an attempt to see the creature's face as it loomed above her. Light faded from view as its shadow engulfed her, and she gulped." 

(Note: I have no idea the context for your sentence, so I took some liberties with the scene.)

Anything you can do to avoid actual size descriptors will allow scenes to have impact when you do use them. After all, there are only so many synonyms for "large" before you'll be repeating yourself.

As for distance, (again some made up scenes), we have preconceived notions of distance inherent to us that can be played upon by how the MC is impacted by a journey:

"She hadn't even worked up a sweat as she approached the stream, so it would serve well as her main source of water."

"Her legs ached by the time she reached the peak, and she heaved in gulps of cool, crisp air. She dreaded the thought of having to hike up here every day. Wasn't there some place closer she could find the herb?"

"She explored around her cave day after day, pushing herself to exhaustion with every trip. Each time the sun was lower in the sky than it had been the day before, upon her return. She had yet to find any evidence of predators. It seemed she would be safe, at least for now."

I hope you don't give up!

I don't really have much to add,  but I wanted to thank everyone for their thoughtful replies! I'll definitely try to stick with it.

Also worth thinking about how people measured distance and time before formal weights and measures were codified. People still talk and think like this, too, and most don't carry around measuring tapes or rangefinders, scales or measuring cups, so it feels more natural than precise measurements when delivered from a character's point of view. People speak in precise measures, but they usually aren't much better than this sort of thing.

Basically, comparative statements and environmental connections are your friend.

Quote:She hefted the sword experimentally; it was shockingly light, no more difficult to swing than her makeshift fishing rod. (As opposed to "...light, barely two pounds in weight.")

Quote:He rose at dawn and broke camp, intent on traveling hard over the savanna until the sun was halfway across its track before stopping to seek shelter from the sweltering midday heat. (As opposed to "...savanna until noon...")

Quote:After dropping the last of the distance, she collapsed against the wall of the ravine, panting. A glance upward left her doubting her own good sense, the ledge she'd descended from was as high as the crown of an old-growth pine, and the surface farther still. (As opposed to "...was 150 feet above her...")

Basically, you want the character to use things she'd be familiar with as reference points, while also making sure that they're things the audience should be familiar with. The average reader doesn't know that pine species generally top out at ~100-200ft, but most of them have probably seen a big old pine tree before and have a rough idea of how high the distance the character is seeing is.

A important thing people often forget is to write like the character would tell the story. A science guy would be more exact for instance.

Allow me to mingle into the discussion. I find all the examples given by the other members correct and very helpful. But I somehow fail to understand where the difficulty of the whole situation comes from. There are some small misconceptions that I would like to brush upon.

1. Numbers
Even in the most primitive society there exists the concept of simple numbers. That is, counting to 5 or 10 since all normal humans have at best 10 fingers (in a fantasy setting it would depend on the species). But I am willing to bet that even a caveman, if asked how many children he has, can say "ten and two more". Counting and numbers come from necessity. So even if a person has no word or understanding of a number such as 357892, he/she can say that "I have ten chickens and another time ten chickens" even without knowing the number twenty. At some point, when we have a very high number, we as humans use simply the descriptives "many", "heard", "flock". The concept about fractions is the same. The ancient people knew the concept of "half" that is less than "one whole". They might have had no idea about a quarter or an eight' but definitely knew that there is something like "the half of a half".

2. Measurements
What do you people have against "feet"? This is one of the most ancient and long-surviving forms of measurements. Even the most primitive person has a concept of length. "A finger", "a palm", "an elbow" (measured from the wrist to the... you guessed it - the elbow), "an arm" (from the tip of the fingers to the shoulder), "an arm-span" (from the fingertips of the one arm to the tips of the other), "a foot". All these measurements are ancient and survived way into the middle ages when people finally had enough from being cheated by merchants with small feet and hands and decided to use a unified metric system.
What about volumes? There is always a "jug", "a bucket", a "barrel".
Then what about height and weight? Many have correctly answered that in the comments above. A comparison with known objects was used. But then again, there was also the unit of "head". There were people who were "two heads shorter" or "a head taller". There was also the most common tool for size comparison - the human. Some statue was "the height of three grown men" or strange creatures "the size of a child/toddler". And before someone says that the use of a "grown man" as measuring standard is sexist - no, it is not. Evolutionary speaking, men are simply taller than women and we as humans tend to use extreme opposites when making comparisons (man vs. child).
As for weight, mainly animals were used. If you have something that weighs as much as a chicken and compare it with "the weight of a horse" it is clear which one is heavier.

3. The concept of time and distance
Even the most primitive civilization has a concept of time. They measure it not by hours but by days, or if exact, by days and nights. The concept of midday and midnight has also been a thing for thousands of years. 
And with the concept of time, the concept of distance can also be explained. Here an example from a hypothetical ancient narrator who has the concept of simple numbers (i.e. he can count on his fingers): "And five times did the sun rise and fall, and three more times after that. And on the fourth dawn thereafter they reached the summit of the mountain." This might not give an accurate measurement of "distance" but we know it is a far-away place if it takes eight days to travel. Another possibility to measure distance even more accurately is by combining time and the speed of different animals (humans included). Here another totally made-up example: "Far away was the town of Ephestos from the royal capital. Even the swift wings of a bird would take five days and nights, and a fast rider would need trice as much". For shorter distances one simply used paces. 

In short, as long one has fingers, arms, and legs; has eyes to see day and night, and does not live in an empty space devoid of animals and plants, I don't see much of a problem substituting different units of measurements instead of using miles, pounds, kilograms, meters, inches or whatnot.