B1.8 Round decimal numbers to the nearest whole number in various contexts.
Activity 1: The Layout of our Classroom
Share the following situation with students:
The layout of our classroom is very important. The way the desks, chairs, tables and all other furniture and materials are placed helps us to be comfortable and to learn. How can we better design our classroom?
Explain to students that when designing a classroom, it is necessary to consider the measurements of the furniture and the classroom. Invite students to measure the length and width of the furniture and classroom. Explain that furniture measurements can be rounded to make a quick calculation to determine the best placement for each piece of furniture. Explain to students that it is necessary to consider the space around the furniture to be able to move around.
In small groups, or individually, invite students to draw plans for the classroom layout according to their vision. Students can calculate, using rounded numbers, the space occupied by each piece of furniture or group of pieces of furniture to determine their location in the classroom.
Activity 2: Snowboarding
Ask students to solve the following problem:
To make a snowboard, a sports equipment manufacturing company uses three pieces of wood, each measuring 49.7 cm. What is the approximate length of wood used for each board?
Allow students to use the strategy of their choice to solve the problem.
Example
|
Hundreds |
Tens |
Ones |
Tenths |
|---|---|---|---|
|
4 |
9. |
7 |
The number in the tenths place is more than 5, so it is necessary to round up to the nearest whole, which is 50.
|
Hundreds |
Tens |
Ones |
Tenths |
|---|---|---|---|
|
5 |
0. |
0 |
Each piece of wood is about 50 cm long, and each snowboard has three pieces of wood, so \(\ 3 \times 50 = 150\). The approximate length of wood used for each board is 150 cm.
Source: translated from En avant, les maths! 4e, CM, Nombres, p. 4.