How to copy value from cell, google sheets?

Question

Google Sheets

Hello!
I’ve been sitting for 3 hours, scratching my head, googling, but I can’t find anything.
In cell A1 we have the current dollar exchange rate, which is taken from the website of the Ministry of Finance automatically.
The value from cell A1 is copied into Cell B1 by the formula (=A1).
Next comes the calculation, for example:
A1 = 25 C1=2($)
D1= C1($2) * B1(25 UAH) = 50 UAH, we had a purchase price in dollars and we converted it to hryvnia.
But, there is one big BUT, if the exchange rate in cell A1 changes, then all calculations change.
Is there any formula like (=A1) only that the value is not equal, but copied from the cell and remains static.
How to make it so that the value is copied from cell A1 and remains static? That is, if A1 changes, B1 will remain unchanged.
I hope I asked my question in an accessible way, because my head is already a mess and it is difficult to formulate something.
Thanks everyone for the replies.

Answer 1

Copy A1 to clipboard and then paste into B1 as Edit->Paste special->Paste values ​​only.

Answer 2

If you need to fix the exchange rate on some date, use the GOOGLEFINANCE function ( code ; [ attribute]; [start_date]; [end_date|number_of_days]; [interval] ) you can substitute any other currencies): In D2 , write the date of purchase. And the exchange rate is tightened from a certain date. Because Since these are historical data, they will not change.