# How to Add (Meso-America Version) (Week 5, Day 2)

Last time we learned how to add like the ancients of Europe, Asia and Africa. This time you have been sent back to ancient Mesoamerica. Good news! This time instead of only rocks you have some ink and some bark! Lets learn how to add Mayan style!

First we need to learn the Mayan numeral system. It is remarkably elegant in its simplicity. There are three symbols that you need to know.

Zero, one and five. (Pay no attention to Tidbit.)

One is represented with a dot, five with a line and zero with a picture of an up-side-down turtle shell. With these three symbols the Mayans were able to represent all the whole numbers. For the numbers up to 19 they had something like a tally system.

But this system could get difficult to handle so instead of continuing to twenty with four lines, they used a place value system similar to the one we used today, only instead of base ten they worked in base twenty.

So twenty would be represented like this:

Thirty (twenty-ten):

Forty:

One Hundred:

So now hopefully you have grasped how to represent numbers in Mayan numerals. Lets get down to the business of actually adding some numbers.

Lets start with forty-two plus ninety-three. Note that since the Mayans wrote their numbers in columns, we will do the addition across the page rather than down the page like we are used to doing with the Hindu-Arabic numerals.

Our initial set up.

Sanitize the result.

Sanitize the result.

What number do we have?

42 + 93 = 135

So now you know how to add like a Mayan! I hope you have gained a deeper insight into the importance a good place-value system has in making elementary arithmetic possible.

## 4 thoughts on “How to Add (Meso-America Version) (Week 5, Day 2)”

1. Amie says:

cool!

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2. C. Robson says:

So why did you not show the turtle shell in your twenties row? That confused me.

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• Reg Robson says:

The turtle shell is equivalent to our “0” symbol. In the number 102, there is nothing in the tens column so we put a zero. We don’t show the fact that there is nothing in the thousands column because it is just assumed. That is we don’t need to write 0102.
If we wanted to write 400 in Mayan numerals we would write:
dot
shell
shell
Standing for one 400, no 20s, and no 1s. In this case we would write a shell in the twenties row. A shell in the twenties row will only happen if the number is big enough, specifically if it is 400 or over. In Mayan numerals all the numbers under 400 can be written in just two rows.
Does that clear up the confusion?

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• Chris Robson says:

Confusion is now cleared. Thanks.

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