Solve problems with or without a calculator Level 4

Find the outcome of a given percentage increase or decrease. e.g. an increase of 15% on an original cost of £12 gives a new price of £12 × 1.15 = £13.80, or 15% of £12 = £1.80 £12 + £1.80 = £13.80. Talk me through how you would increase/decrease £12 by, for example 15%. Can you do it in a different way? ................
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