Balanced ternary

Balanced ternary is a type of numbering system with a base of 3.

The most common numbering system in use today is decimal. Decimal has a base of ten, so it has 10 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. Ternary has a base of three, so it has only 3 digits: 0, 1 and 2. Balanced ternary also has a base of three, but it uses the digits -1, 0 and 1.

Like decimal, balanced ternary uses a place value system. Each place value is equal to the previous place value multiplied by the base. In decimal, we have a one's place, a ten's place, a hundred's place, a thousand's place, and so on. In balanced ternary, we have a one's place, a three's place, a nine's place, a twenty-seven's place, and so on.

Balanced ternary allows you to write numbers less than zero without needing a dedicated minus sign; if the digit with the biggest place-value is negative, the entire number is negative. Another benefit is that when it comes to computers, there are much fewer rounding errors.

Comparing systems

Most balanced ternary systems use the letter T or the symbol ! for the -1 digit. This article will use the letter T.

Base10TernaryBalanced
Ternary
B. ternary
expanded
1111x1
221t1x3 + -1x1
310101x3 + 0x1
411111x3 + 1x1
5121tt1x9 + -1x3 + -1x1
6201t01x9 + -1x3 + 0x1
7211t11x9 + -1x3 + 1x1
82210t1x9 + 0x3 + -1x1
91001001x9 + 0x3 + 0x1
101011011x9 + 0x3 + 1x1
Base10TernaryBalanced
Ternary
B. ternary
expanded
-1-1t-1x1
-2-2t1-1x3 + 1x1
-3-10t0-1x3 + 0x1
-4-11tt-1x3 + -1x1
-5-12t11-1x9 + 1x3 + 1x1
-6-20t10-1x9 + 1x3 + 0x1
-9-21t1t-1x9 + 1x3 + -1x1
-8-22t01-1x9 + 0x3 + 1x1
-9-100t00-1x9 + 0x3 + 0x1
-10-101t0t=1x9 + 0x3 + -1x1