If you want to store the values decimals like 3.5, 4.05, 9.2 and all.
You can store it in a Double Datatype variable.
Go to Variable panel → Hit on the Variable type → Click on browse for more types → Search for System.double.
Check the below image for better understanding.
The difference between the double and decimals is the Double data type is faster and requires less memory, but it is subject to rounding errors. The Decimal data type retains complete accuracy to 28 decimal places .