If you use the 'right align' tag, you can get the figures lined up. (See for advanced code options, or just use the icons above the composition box.)
Rent allowed 10,000
Tax 4,200
However, if you're a perfectionist, the text still looks a little messy because the whole line is right-aligned, not just the figures, so the text is misaligned. You could correct this by using a fixed width font such as courier and using a character such as a full stop as a spacer, with a pale font that won't show up too badly.
Anyone know how to input info in column order so that a column of numbers data etc can appear as they were typed. I tried using space bar & tab bar but when you post the AAM site does not recognise them
I entered the following details so that the 4,200 is directly under the 10,000
Rent Allowed 10,000
Tax 4,200
I would have tought this was fairly basis this being a financial site