Idea 15of 22Builds onAdd, then divide by how many
The mean of decimal data
How do you share out 4.2, 3.6 and 5.1?
Today you'll discover
- adding decimals for the total
- dividing a decimal total
Think firstSeedlings 4.2, 3.6 and 5.1 cm tall
What is the mean height of the seedlings?
Decide first, then press Next. Read the working above the stacks.
Three bars for seedlings 4.2, 3.6 and 5.1 cm tall. Then the working: total 4.2 + 3.6 + 5.1 = 12.9, and 12.9 ÷ 3 seedlings = 4.3 each, with all three bars level at 4.3. The last step shows four pumpkins: 2.5, 3.0, 3.5 and 4.2 kg.
See the whole ideathe big idea and the key word, in one place
The big idea
For decimal data, line up the decimal points to add, then divide the total as usual.
Easy to get wrongThe mean and the median of decimal data are often close but not equal. For the pumpkins, the mean is 3.3 and the median is 3.25.
Key word
- decimal point
- the dot between the ones and the tenths; line the points up to add decimals
Ready to use it?
- Find the mean of decimal measurements.