ROUND Function: Round Off, Round Down, or Round Up Numbers
By using the ROUND function in a formula, you can round off numbers to the specified number of decimal places.
You can also use the ROUNDDOWN function or the ROUNDUP function to round down or round up numbers.
Using ROUND Function
ROUND(Number, Number of decimal places) Rounds off the number. You can specify the number of decimal places for rounding off. 
ROUNDDOWN(Number, Number of decimal places) Rounds down the number. You can specify the number of decimal places for rounding down. 
ROUNDUP(Number, Number of decimal places) Rounds up the number. You can specify the number of decimal places for rounding up. 
For the fist argument (Number), specify the field code of the Number field.
For the second argument (Number of decimal places), specify the number of decimal places for rounding, rounding down, or rounding up. You can omit the second argument (Number of decimal places) for any of these functions. If you omit the second argument, the argument is considered as '0'.
Formula Example
Formula (Calculation of price with tax): ROUND(pre_tax_price * 1.1)
Multiply the pretax price by consumption tax rate (1.1), and round off the number to calculate the tax included price. In this example, the second argument '0' is omitted to get an integer value. 
Specifying the Number of Decimal Places
Specify the number of decimal places for rounding, rounding down, or rounding up.
For example, if you specify '2' as the number of decimal places for the ROUND function, the third decimal place is rounded off to show the result.
If you specify a negative number as the number of decimal places, the integral part is rounded, rounded down, or rounded up. For example, if you specify "2" as the number of decimal places for the ROUND function, the tens place is rounded.
Number  Number of decimal places  Decimal place to be rounded off, rounded down, or rounded up  Result 

1234.567  3  4th decimal place  Rounding off: 1234.567 Rounding down: 1234.567 Rounding up: 1234.567 
1234.567  2  3rd decimal place  Rounding off: 1234.57 Rounding down: 1234.56 Rounding up: 1234.57 
1234.567  1  2nd decimal place  Rounding off: 1234.6 Rounding down: 1234.5 Rounding up: 1234.6 
1234.567  0  1st decimal place  Rounding off: 1235 Rounding down: 1234 Rounding up: 1235 
1234.567  1  ones place  Rounding off: 1230 Rounding down: 1230 Rounding up: 1240 
1234.567  2  tens place  Rounding off: 1200 Rounding down: 1200 Rounding up: 1300 
1234.567  3  hundreds place  Rounding off: 1000 Rounding down: 1000 Rounding up: 2000 
Steps
This section describes the way to multiply the pretax price by consumption tax rate (1.1), and round off the number to calculate the tax included price.

Open the screen to set forms, place the Number field in the form, and specify "pretax price" as the field name and "pre_tax_price" as the field code.

Place the Calculated field in the form, and specify "tax included price" as the field name.

Enter the following formula in the "tax included price" field.
 ROUND(pre_tax_price * 1.1)

Save the form, and update the app.
If you enter the pretax price, the price is multiplied by consumption tax (10 %), and the result value (tax included price) is displayed.