This is a comment on Blank page after install. 18.04 LAMP, posted by WikiAdmin at 12.12.2019 21:16

View source for Re: Missing BC Math or GMP extension

PHP Fatal error: The **BC Math** or **GMP** extension is missing. The Hashids lib and the URI router is therefore failing. 

The installer indicates whether all required **PHP extensions** are available.

file:/wackowiki_r60_en_install_2.png

**BC Math** (##php-bcmath##) should be available if you did the following:
%%
apt -y install
       php
       php-common
       php-bcmath
       php-ctype
       php-gd
       php-iconv
       php-json
       php-mbstring
       php-mysql
       apache2
       libapache2-mod-php
       mariadb-server
       unzip
%%

Please install **all** required **((/Doc/English/Requirements PHP extensions))**: bcmath, ctype, gd, iconv, json, mbstring, openssl, pcre, spl.
Then try it again.

I suggest you to install already **R6.0.rc1** because this will save you the migration to Unicode later on. R6.0.0 will be out soon.