oku yen to usd artisan command

OkuCalculator.php

<?php

namespace App\Console\Commands;

use Illuminate\Console\Command;

class OkuCalculator extends Command
{
    /**
     * The name and signature of the console command.
     *
     * @var string
     */
    protected $signature = 'oku:usd {oku} {exchange?}';

    /**
     * The console command description.
     *
     * @var string
     */
    protected $description = 'Command description';

    /**
     * Create a new command instance.
     *
     * @return void
     */
    public function __construct()
    {
        parent::__construct();
    }

    /**
     * Execute the console command.
     *
     * @return int
     */
    public function handle()
    {
        $exchange = $this->argument('exchange') ?? 0.0096; // As of 1/30/21

        $yen = 100 * 1000 * 1000 * $this->argument('oku');

        $dollars = $exchange * $yen;

        $this->info($this->argument('oku') . ' OKU YEN is equal to ' .  number_format($dollars, 2). ' dollars.');
        return 0;
    }
}