Rounding Difference

[zqlcancer]

In my attached sample file you can see I am trying to calculate the tax amount by multiple rate and tax base amount, then use it to minus output tax. I use the round to keep 2 decimals but why I still have the difference for line 2? Is this a bug?

Rate	Output tax	Tax base amount	Tax Amount	Difference	round value	round difference
20	(88.32)	(441.60)	(88.32)	0.00	(88.32)	(0.00)
20	(1,094.1000000000)	(5,470.52)	(1,094.1040000000000)	(0.0040000000001)	(1,094.1000000000)	(0.00000000000023)

[Clifford_Coon]

Hi,

One simple approach it to change your types from double to FixedDecimal   (precision 19 Scale 2) for the columns you are creating in the foumula tool.  

When I idd, i get this:

Rate Output tax     Tax base amount Tax Amount Difference round value round difference
20     -88.32            -441.6                 -88.32           0.00         -88.32        -0.00
20     -1094.1           -5470.52            -1094.10     -0.00         -1094.10     -0.00

[PhilipMannering]

☝️ What @Clifford_Coon said. Computers aren't good at decimals, they're good at binary. Use a Fixed Decimal (Precision ≈ 19 and Scale = 2) to only show the first two decimal places.