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This is often not what you want with monetary calculations. You want the rounding: you'll be making a payment of $25.86, not $25.85714285714... But you just want to make sure that the next payment is $25.85, not $25.86 or $25.857142851, and that all 7 payments together equal $181 and not $181.02.

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I can't speak for C# but the Python Decimal type handle significant figures correctly.

> The decimal module incorporates a notion of significant places so that 1.30 + 1.20 is 2.50. The trailing zero is kept to indicate significance. This is the customary presentation for monetary applications. For multiplication, the “schoolbook” approach uses all the figures in the multiplicands. For instance, 1.3 * 1.2 gives 1.56 while 1.30 * 1.20 gives 1.5600.

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