Calculate Adding Extra Decimals

[hakan_cetinkaya]

Description

Calculate type question behaves differently on certain numbers and creates unnecessary decimal digits.

Related: Decimal creating more digit in decimal part

Steps to Reproduce

A)

1. Create an integer type question (Q1)
2. Create a calculate question (C1) with a simple ${Q1} * 1.1 formula.
3. Create a note to display ${C1}
4. Write 100 to Q1.
5. The note displays 110.00000000000001 instead of 110

B)

1. Create two decimal questions Q2 and Q3
2. Create a calculate question (C4) with a simple ${Q2} + ${Q3} formula.
3. Create a note to display ${C4}.
4. Write 2.32 and 1.32 to Q2 and Q3.
5. The note displays 3.6399999999999997 instead of 3.64

Expected behavior

The expected behavior is to calculate works same in every number.

Actual behavior

The calculate works different for some numbers. See screenshots for different behaviors:

Additional details

• So far, I’ve tested and confirmed that these numbers create some sort of problem in the following calculation: integer * 1.1 : “3, 6, 7, 11, 12, 100, 200, 400, 700, 800”

• There is a form where you can check additional calculations:
  Enketo Express for KoboToolbox

• There is an xlsform with additional operators. Feel free to check it yourselves:
  Calculate Problems.xlsx (10.1 KB)

[Dnes]

we can use the round-off.

Rounding off to lower value

Hi, The truncate function does not seem to be working in Kobo. I want to round off the value to the lowest integer value. For example, 5.7 should be rounded off to 5. Is there a way to do this on Kobo?

[Jan_L]

I have done this, but it mess up other number that doesnot need to be round off tho,

[hakan_cetinkaya]

@Dnes

we can use the round-off.

I don’t think rounding-off always would solve the issue for everyone.

[Okard]

Hi @hakan_cetinkaya , do you find any solution?

@Kal_Lam would you mind suggesting please?

[hakan_cetinkaya]

@Okard, Unfortunately not.

[hakan_cetinkaya]

You can see another occurance of this bug in @Kal_Lam’s answer, see the second screenshot, it should be:

0.98 - 0.91 = 0.07

but it is

0.98 - 0.91 = 0.0699999999995

Trying to calculate the difference (instead of substraction)

@prasenjit_mondal, you should be able to do this by following the instructions outlined below: In the survey tab of your XLSForm: [image] Data entry screen as seen in Enketo: _when the difference is less than 0.5) [image] Data entry screen as seen in Enketo: _when the difference is greater than 0.5) [image] Reference XLSForm: Absolute Value.xlsx (8.5 KB)

[hakan_cetinkaya]

You can see another variance of this bug when @inigo-blonk tried to use:

99.3 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 as a calculation.

in here:

Calculate field bug

Description When using a calculate number as a relevant, the number is not well calculated. Steps to Reproduce …Use a sum calculate based on a decimal inputs of a number of questions …In this case the numbers asked for are supposed to add to a 100 …The result number is 99.9999999 Expected behavior The sum of the numbers should match the sum of the inputs Actual behavior The number adds up to a number not correct [check-kobo]