How do I round a number to the nearest 5 or 10?

[font=verdana,arial,helvetica][size=1] [/size][/font]I have the following numbers: 10.98, 1.23, 5.66.
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I want to round the last digit to the nearest 5, to get: 11.00, 1.20, 5.70.

What’s the best way of doing this?

Any help would be appreciated.