1900On 20 Jun, 23:28, wrote:
i am trying to find out the value of a banknote issued by the
government of the straits settlements. dated 03/01/1900. $5. tan
background w/grey print. a/6 99010. fancy flowers and tiger on back.
also red stamp.

What condition is it in?

It is worth many many thousands of dollars.

This auction is taking place in July in Singapore

http://www.spink.com/auctions/pdf/8014pages.pdf

52*
Government Issue, $5, 1 March 1900, serial number
A/6 39960, black on pale yellow-cream, value in lilac
underprint low centre, arms top centre, three signatures
low right, value at centre (Tan S 3a), a presentable fine, very
rare
Estimate S$7,000-8,000

259*
Government Issue $5, 1 March 1900, serial number
A/7 16433 black text on pale beige background, arms top
centre, value in lilac underprint low centre, value at centre
and all corners, three printed signatures at low right,
reverse black and beige, tiger at centre (Tan S3a) very good,
rare
Estimate S$3,000-4,000

Be aware that 'Fine' is actually not particularly good condition, if
the one you are enquiring of is crisp with only one or two folds it
will be worth much more.

I would await the actual selling price.