Write a mini-analogue of Google tables. In a web page, make a table 4 by 4 columns.
The columns have a letter designation, the rows are numeric.
In the cell, you can write a number or a formula, the first character of which will be '='
In formulas, it is possible to refer to a cell by its position column+row.

Available operations: + - / * ( )

After pressing enter, it is necessary to defocus the cell and calculate the values of the table. You need to calculate the values on the server side. Server stack - java + spring framework"

Sending occurs after cell unfocus or pressing Enter