Identify and order decimals to three places.
Number Framework Stage 7
Give the students calculators. Pose the problem “Jane has $6 to share among five people. How much does each person get?” Write $6 ÷ 5 on the board or modelling book. The students carry out the operation 6 ÷ 5 = on the calculator, and get 1.2. Ask the students what 1.2 means in money. Discuss, with the aid of 10-cent coins if needed, why one-tenth of a dollar is 10 cents. So two-tenths of a dollar is 20 cents, and so 1.2 = $1.20.
Record $6 ÷ 5 = $1.20 on the board or modelling book.
Repeat for: $7 ÷ 5, $6 ÷ 4, $4 ÷ 5, $14 ÷ 4, $13 ÷ 2 ...
Activity
“Sarah pays $5 for 4 kilograms of apples. How much is this per kilogram?” Get the students to work out 5 ÷ 4 on a calculator. The answer of 1.25 looks familiar in money. Discuss why one whole and two-tenths and five-hundredths is one dollar 25 cents.
Repeat for: $7 ÷ 4, $13 ÷ 4, $3 ÷ 4, $14 ÷ 8, $20 ÷ 16.
Extension Activity
The students use calculators to solve problems like $23 ÷16; $13.89 ÷ 11; $345.78 ÷ 17; $14,567.67 ÷32; $290 ÷ 64 ...
The students then round the answers to the nearest one cent, or to the nearest five cents. Drawing decimal number lines may help the students visualise the rounding.