adding the balance of two accounts in ledger-cli or hledger plain text accounting

Question

I am trying to get the total balance of two accounts instead of all of them with the usual hledger bs or hledger bal:liabilities I want to save this as an alias in zsh to check it easily.

I ended up switching to ruby because I guess my bash and zsh skills aren't that great. And aren't you supposed to use a scripting language when you need more than 3 lines in shell? Can you think of a cleaner way to do this? How could I do this in zsh?
I tried installing bc. But had trouble with the string_to_float in zsh.

echo "scale=2; 22/11" | bc
2.00

hledger bal Liabilities:0372        outputs   99.11
hledger bal Liabilities:6154        outputs 8888.44

#!/usr/bin/env ruby
puts "Current Bal @ BoA"
## get balances
bal0372=%x{hledger bal Liabilities:0372 | tail -n 1 | sed 's/ //g' | sed 's/-//g'}
bal6154=%x{hledger bal Liabilities:6154 | tail -n 1 | sed 's/ //g' | sed 's/-//g'}
## remove new line /n


string6154=bal6154.chomp
string0372=bal0372.chomp

## convert string to number

float0372=string0372.delete(",").to_f
float6154=string6154.delete(",").to_f
## add
total=float0372+float6154
## output to screen
## add back commas for readability
puts total.to_s.reverse.gsub(/(\d{3})(?=\d)/, '\\1,').reverse