How do I deduct tax from amount?
1.Goto Transaction > Sale.
2.In sale frame you can tick checkbox of 'Deduct tax from amount.
3.If you want to deduct Tax from all transaction except sale then you need to enable settings of deduct tax from Amount.
4.for that Go to Setup > Configuration > Inventory Setting > click on 'Deduct Tax From Amount By Default(except sale)''.
Then tax will be deducted from amount for all sale transaction.