Negaternary is a numeral system in which numbers are written as sums of successive powers of -3. The three digits are 0, 1, and 2. The advantage of using a negative radix is that there is no longer a need for a minus sign; negative numbers can be written the same way as positive numbers. (Compare with balanced ternary in which the radix is positive 3 but the digits are -1, 0, and 1.) Here are the integers from negative ten to ten in both decimal and negaternary:
-10 1212
-9 1200
-8 1201
-7 1202
-6 20
-5 21
-4 22
-3 10
-2 11
-1 12
0 0
1 1
2 2
3 120
4 121
5 122
6 110
7 111
8 112
9 100
10 101
As in negabinary, negative numbers have an even number of digits, and positive numbers have an odd number of digits.