Update

number.md

@@ -110,7 +110,7 @@ There are different types of numbers, in mathematics we classify them into [sets
       - **[imaginary](imaginary_number.md)**: Have the same properties as real numbers but lie in another dimension, on a line perpendicular to the real number line, going through 0 -- they are connected to real numbers by the fact that imaginary unit ([i](i.md)) squared equals minus one. E.g. 0, 3i or -i.
       - **R: [real](real_number.md)**: Measure any continuous one dimensional quantity (such as height or length), the line they form is continuous. E.g. -0.3, [pi](pi.md) or cube root of 10000.
         - **negative**: Smaller than zero. E.g. -1, -123 or -1000.
-        - **non-negative**: Aren't negative. E.g. 0, 1 or 1000.
+        - **R0+: non-negative**: Aren't negative. E.g. 0, 1 or 1000.
         - **R+: positive**: Greater than zero. E.g. 1, 456 or 1000.
         - **irrational**: Aren't rational. E.g. [pi](pi.md), minus [e](e.md) or square root of 2.
         - **Q: [rational](rational_number.md)**: "Fractions", countable set, can be written as a fraction of two integers; between any two there is always another one, so they are very densely "packed", though the line they form is not truly continuous. E.g. -2/3, 0.12345 or 2135.
@@ -242,4 +242,4 @@ Here is a table of some notable numbers, mostly important in math and programmin
 | [j](j.md)                           |                     | k * i                                    | one of quaternion units                                 |
 | [k](k.md)                           |                     | i * j                                    | one of quaternion units                                 |
 
-TODO: add some p-adic number to the table
+TODO: add some p-adic number to the table