Planning and Activities
Day 1 Teaching
Say you have 52p and spend 47p. Mark 52p on a 0–£1 penny line. Explain: We can count up to find a difference. Mark on 47p, and cross out pennies up to 50p, then to 52p: 3p + 2p is 5p left. Repeat for £63 – £56, hopping £4 to £60, then another £3 to find the £7 difference.
-- Discover how much money is left by calculating differences using a penny line.
Day 2 Teaching
Show a toy frog and agree a name. Explain that maths Frog helps us subtract by hopping up the number line to find a difference. Model how Frog hops from 37 to 45 on the bead bar to solve 45 – 37. Repeat several times with other problems on beaded lines.
-- Calculate the difference between two 2-digit numbers by counting up with Math Frog.
-- Play ‘snatch the match’: subtract two 2-digit numbers by counting up with Maths Frog.
Day 3 Teaching
Write 53 - 47 on the board and read it as 53 subtract 47. Model counting back; then use Frog to find the difference. Compare the two strategies. Use Frog to solve 54 – 48, 23 – 17 and 65 – 54.
-- Solve subtractions using beaded, landmarked or empty number lines.
-- Suggest the subtraction by watching Maths Frog complete jumps on a bead bar.
Day 4 Teaching
Show how solve 62p – 47p using a 0–£1 penny line. Cross out up to 47p. Then demonstrate drawing 3 hops: 47 to 50, then 50 to 60 and 60 to 62. Write 85 – 68 and show how Maths Frog can help us count up. Repeat with 61 – 47 on a landmarked line.
Use the ‘Frog’s Busy Day’ in-depth problem-solving investigation below as today’s group activity.
Or, use this activity:
-- Solve subtractions of 2-digit numbers with answers greater than 10.
Day 5 Teaching
Discuss how we may want to solve 53p – 11p and 60p – 47p in different ways. The first can easily be done by counting back. The second may be more easily solved with maths frog. Repeat to choose a different strategy for 62 – 25 and 67 – 25.
-- Investigate an efficient method for subtracting (counting up or back).