Percents (an introduction)

Opening: Video (leg...) In groups, we will work on this problem with whiteboards.
Assessment Review
Percents
Take an A4 piece of paper and hold it landscape:

Cut 5 cm strips from the paper.
One strip stays whole - original
Other strips need a portion cut out: 25% of original, 20%, 12%

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Problems
(For each, please make sketches as modeled above.)
1. If Strip #1 represents the whole (100%), how much is a 25 % increase? A 25% decrease?
2. If Strip #1 represents the whole (100%), how much is a 20 % increase? A 20% decrease?
3. If Strip #1 represents the whole (100%), how much is a 12% increase? A 12% decrease?
4. If Strip #1 is 30 cm long, how much is a 25 % increase? A 25% decrease?
5. If Strip #1 is 30 cm long, how much is a 20 % increase? A 20% decrease?
6. If Strip #1 is 30 cm long, how much is a 12% increase? A 12% decrease?