Here are a couple of games to practice this concept
Scooter Quest Soccer Shoot Decimal Sharks
Rounding decimals can have lots of uses. Sometimes we just need to estimate amounts. Like if we want to know how much our groceries will cost or if we are 'pricing-up' a DIY job.
Make a shopping list of 10 items and find the exact prices of these objects on the countdown website. Write down the price of these objects in your books.
Next, round the prices up or down to the nearest dollar and add up the total.
Next round the price up or down to the nearest 10c and add them up. Is there much difference?
Finally, add up the actual price using the exact prices. How different are the prices?