Limit input of "other" to >50

Hello,

I have a form here: https://www.fingalsbakery.com/invest.html which is working pretty well. The only problem is in the "I would like to invest" section. Curerntly it has 4 options plus "other":

£50

£100

£200

£500

Other

I would like to restrict the users' input of "Other" to an amount greater than 50, but I am not sure how to do this. I've tried adding a conditional logic thing: I tried adding a Calculation to set that field's value to the maximum of either "50" or the "field's existing value", like this:

...but it didn't do anything. Is this the correct syntax for the "max" function? This is not ideal - I'd much prefer a message to pop up or something if a user types in, say, "45". Forcing the value to change to "50" could be misleading for the user.

Do you have any suggestions?

Thanks in advance for any help!

~ Paul

Max function will output the number with the highest value so that's a good workaround.

The other workaround is to get the number value using the form calculation widget. Then add a show/hide condition that if the invest field is less than 50, show a text message and hide the submit button to prevent the user from submitting the form until they correct the error.

Example:

Hope this helps!

Thanks! That did the job perfectly.