1% - divide by 100, 5% - divide by 10 and half it, 10% - divide by 10, 20% - divide by 10 and then double it, 30% - divide by 10 and then multiply by 3, 50% - divide by 2, 75% - divide by 4 and then multiply by 3, 25% - divide by 4, 80% - divide by 10 and then multiply by 8, 3% - divide by 100 and then multiply by 3,

Finding key percentages without a calculator

Leaderboard

Visual style

Options

Switch template

Continue editing: ?