Term 1 · Week 7 · Percentage increase and decrease
NameDate
For the teacher. This is for a learner who adds and subtracts percentages directly, or reads 20% as "divide by 20". It is not a shortened copy of
worksheet.html — it is a different route to the same competency, starting further
back. Task 4 is the first two-step change on worksheet.html. Show each worked example first and let the learner copy the
method, never the answer. If task 1 will not come: If task 1 will not come, stay on 10% of round hundreds until it is automatic. Everything else is built from it.
1Ten per cent first
— targets 20% read as divide by 20
Say: “Move the decimal one place. That is all.”
Worked example. 10% of ₱250 is ₱25. Ten per cent means ten per hundred, so one tenth.
10% of ₱400 = ______
10% of ₱90 = ______
10% of ₱1 250 = ______
2Build the rest from ten
— targets treating each percentage as a separate skill
Say: “Twenty is two tens. Five is half a ten.”
Worked example. 20% of ₱250 = two lots of 25 = ₱50. 5% of ₱250 = half of 25 = ₱12.50.
20% of ₱400 = ______
5% of ₱400 = ______
30% of ₱90 = ______
3Name the base, then change it
— targets losing track of what the percentage is of
Say: “Per cent of WHAT? Write that number down first.”
Worked example. ₱200 up by 15%: base is ₱200, 15% of it is ₱30, new price ₱230.
₱500 up by 10%. Base: ______ Change: ______ New: ______
₱80 down by 25%. Base: ______ Change: ______ New: ______
4Two changes, two bases
— targets "up 20 and down 20 is zero"
Say: “Write the base again before the second change.”
Worked example. ₱100 up 20% → ₱120. Then down 20% — of 120, not of 100 — is ₱24, so ₱96.
₱200 up 10%, then down 10%. First base ______ → ______ Second base ______ → ______
Write in words why the answer is not ₱200: ______________________________________
Answer key — not printed on the learner's copy
₱40 · ₱9 · ₱125
₱80 · ₱20 · ₱27
500 / 50 / 550 · 80 / 20 / 60
200 → 220, then 220 → 198 · the second percentage was taken from a bigger amount