Yes, you will need to get the value of textbox in a variable in JS and then run it on an event like keydown/keyup get the value in next textbox/below.
like:
var tb_value=jQuery('input[type="text"]').val()
jQuery('input[type="text"]').keyup(function() {
var actual_val=Number(tb_value * 100)
jQuery('input[type="text"]').val(actual_val)
})

Remember I am assuming you will be using 2 textboxes so use eq() as well to get and set the values into!

Thanks, graphulp5! I'm still a bit confused. I think the second text box, for actual_val, would be in a separate question (but on the same page), right? I'm a bit confused about whether the JS would be associated with the first question, the second, or both, and also how to use eq() to retrieve actual_val and pipe it into the second text box.

That will be in the same question in onReady function, for that we can use keydown function.

To retrieve the value we will need to use eq() to get the required value.

I'm sorry to be so slow, but I've been playing with a number of iterations and haven't been able to set this up correctly. Would it be straightforward to provide a MWE? Thanks again.

Not sure how many textboxes you will be adding but it should be somewhat like below;
var tb_value=jQuery('input[type="text"]').eq(0).val()
jQuery('input[type="text"]').keyup(function() {
var actual_val=Number(tb_value * 100)
jQuery('input[type="text"]').eq(1).val(actual_val)
})

Thanks so much!