Year 6 · Pie Charts, Line Graphs and the Mean · Summary

Year 6 Pie Charts, Line Graphs and the Mean: summary and key words

Part of the Year 6 pie charts, line graphs and the mean chapter. Chapter overview · whole chapter on one page

Chapter summary

Skill	Method
Pie chart	The whole pie is 360 degrees, and it is 100 per cent. The sectors add up to the whole.
Angle of a sector	Fraction of the whole, times 360 degrees. Per cent can be used the same way.
Number in a sector	Angle ÷ 360 × total, or per cent ÷ 100 × total.
Drawing a pie chart	Write each group as a fraction of the total, times 360. The angles must add up to 360.
Line graph	Read the point, go across to the scale. Join the points in order with straight lines.
Change and rate	Change = end value minus start value. Rate for each hour = change ÷ number of hours.
Mean	Mean = total ÷ number of values. Count every value, including a zero.
Totals and missing values	Total = mean × number of values. Missing value = total minus the values you know.
Two groups	Add the two totals, then divide by the number of values in both groups.

I can read the per cent and the angle of a sector on a pie chart.
I can find the number in a sector from its angle or per cent, when the total is known.
I can work out the angle of each sector from a table, and check that the angles add up to 360.
I can read values from a line graph, and plot points on a scale.
I can solve problems with line graphs: differences, totals, the biggest rise and the average change for each hour.
I can find the mean of a set of values, and count every value, including a zero.
I can use the mean to find a total or a missing value, and explain what the mean does and does not tell us.

Pie chart: A circle split into sectors, where each sector shows a part of the whole.
Sector: A slice of a pie chart, with its own angle and its own share of the whole.
Per cent: Out of 100. A whole pie chart is 100 per cent.
Line graph: A graph that marks a point for each time or week, and joins the points with straight lines.
Scale: The numbers up the side of a graph, which show the value of each point.
Gridline: A line across a graph that helps you read a value exactly.
Mean: The average: the total of the values divided by the number of values.
Total: All the values added together.
Rate: How much something changes for each unit, such as each hour.
Average: A single value that represents a set of values. In this chapter, the average is the mean.