Remember that it is often more important for your students to be able to estimate effectively than to calculate accurately. Encourage them to find strategies to help them estimate each day. For example, one strategy might be to visualise breaking up a large quantity into tenths. Roughly work out how many in that tenth and then multiply by 10 to get your estimate. How many bananas do you think are in this pile? How does your estimate compare with a friend’s estimate? Is it in the right ballpark? How do you know?