Lay out the money on the table. This will make it easier to separate the money for counting to find out the number which must be rounded.
Round the number up to the nearest $10 amount (10, 20, 30, 40) if the total that was counted ends in 5 or more. For example, if the total is $46, it will be rounded up to $50. Rounding up is good for finding out high estimate of money totals.
Round the total money down if the total number ends in 4 or less. This helps to give low estimates on monetary totals.