rounding down to nearest 3 decimal places after the decimal point

hi guys

i have the following in cell S11

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T6 is a whole number always lets say 3 in this example
cells u4 or u5 may not be whole numbers
for example if cell U4 is 0.90166666667 and U5 is 1.500

then i get the answer
3 units @ 0.90166666667 x 1.500

so what i really need it to read is
3 units @ 0.901 x 1.500

thanks in advance

Thanks SHG