Converting currency using an exchange rate, and working with ratios

Task goals

• Convert an amount from NZD to a foreign currency using a given exchange rate (e.g. 1 NZD = 0.90 AUD) via the unitary method.
• Convert an amount from a foreign currency back to NZD using a given exchange rate.
• Write a ratio from a described quantity (e.g. the ratio of red to blue marbles) and simplify a ratio to its lowest terms.
• Use a given ratio to find an unknown quantity from a known one (e.g. how many oranges go with 4 apples in a 2:3 ratio).
• Share an amount in a given two-part or three-part ratio, giving all resulting amounts.
• Round a currency conversion to the nearest cent, and apply a percentage commission to a converted amount.
• Compare two different exchange rates or kiosks for the same conversion, and solve multi-step problems that chain a conversion with a fee, a rate change, or a second conversion.
• Apply a ratio to a real quantity in context, including three-part ratios and map-scale problems, to find an unknown share or distance.