Erin buys 4 packs of potatoes costing £2 each, 2 packs of carrots for £3 per pack, and 5 turnips costing 70p each. If she pays with a £20 note, how much change would she get in pounds, £?

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?