Planning and Activities
Day 1 Teaching
Use javelin throws as a context to show how we can count up using Frog from 9.56m to 11.32m. Find other differences in throws measured in metres using Frog to count up. Ensure children are familiar with recording on an empty number line.
-- Explore differences between height and stride length in younger children.
-- Investigate pairs of lengths with given differences.
Day 2 Teaching
Display a table of distances, in which the lengths can include one or two decimal places, e.g. 5.3m and 4.56m. Use Frog (counting up) to subtract pairs of numbers with different numbers of decimal places. Ensure children are comfortable with the empty number line used in this way.
Use the ‘Decimal differences’ in-depth problem-solving investigation below as today’s group activity.
Or, use these activities:
-- Calculate height differences between 2m and 4m.
-- Investigate missing number subtractions.
Day 3 Teaching
Show children a table of prices from two bike shops. Use this to construct problems involving finding differences between amounts. Use counting up (Frog) to solve subtraction word problems.
-- Solve subtraction word problems, choosing an efficient strategy.
-- Rank subtractions in order of difficulty; choose a strategy to solve them.