calculation problem!

[XIII]

i just coded a calculator for forex that calculates pivot and resistance points for currencies, but it calculates it and gives results with this format : xx.xxxxxxxxxxx, i need to get results to the nearest xx.xxxx so i don't need these 11 digits, just need it to give the nearest 4 digits, what should i add to my code?

[barand]

$n = 12.12345678;

echo number_format ($n, 4);

//or 

printf ('%0.4f', $n);

[XIII]

thank you so much, done