How to set maximum value of float in the migration laravel?

I want the maximum value entered into the field amount is 900000000

In the migration I set this :

$table->float('amount', 10, 2);

If I input data 900000000 in the mysql, there exist error :

Out of range value for column 'amount'

I give some example from my data amount :

900000000

800100200,2

1000300,32

10100000,44

etc

How an I solve this problem?

via Chebli Mohamed