Unit 7 · Data and Percentage
Oceantown Currencies — Conversion Chain
Lesson 2 of 9
Five made-up coins in Oceantown: azzes, bayos, cotts, duits and enits. Four conversion rates are given. How many of the smallest coin fit into the largest? Chain the multiplications one step at a time.
Chained unit conversion questions appear regularly on NSW Selective TS Mathematical Problem Solving. The values always chain neatly — each step is a single multiplication. The trap is skipping a step or multiplying in the wrong direction.
The examiner tests whether students can (a) read each conversion in the correct direction (bigger unit = more of the smaller), (b) chain four multiplications without error, and (c) avoid the trap of stopping too early (after only three steps, you get 16 — option A — which is wrong).
A fictional currency (or measurement) system gives a chain of conversions from smallest to largest unit. Students must find how many of the smallest unit fit into the largest by multiplying step by step.
Best approach: Work from the smallest unit up: 1 bayo = 4 azzes. 1 cott = 2 × 4 = 8 azzes. 1 duit = 2 × 8 = 16 azzes. 1 enit = 4 × 16 = 64 azzes. Multiply at each step and don't stop early.
Question
In Oceantown there are five different coins: azzes, bayos, cotts, duits and enits.
There are 4 azzes in 1 bayo, 2 bayos in 1 cott, 2 cotts in 1 duit, and 4 duits in 1 enit.
How many azzes are in 1 enit?
Select an answer to see the explanation.
Give Your Child the Best Chance at Selective Entry
Join NSW families preparing their children for the Selective Schools Placement Test with the most realistic online Selective practice tests available. First tests free—no credit card required.
Claim Your Free Selective Practice Tests