You can't deduct a vague or indefinite amount, or a range. You have to deduct the exact amount that you donated. But you don't have to list each donation individually. You can enter one donation for the total amount to a charity named "Various charities." Only the total actually appears on your tax return, not the names of the charities. But you must keep the individual receipts for at least three years so that you can justify the total amount if the IRS questions it.