B1.3 Round whole numbers to the nearest ten, hundred, or thousand, in various contexts.
Activity 1: Calling Out the Numbers
Prepare cards like the ones below using numbers up to 10 000 and with rounding to the nearest ten, hundred, or thousand (or all three).
| Rounding |
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I have 3200. Who has the number 12 452 rounded to the nearest thousand? |
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I have 12 000. Who has the number 3152 rounded to the nearest hundred? |
Distribute all the cards to the students. Depending on the number of students in the class, some students may receive two cards.
Choose a student at random and ask them to read the question on their card (Who has the number… rounded to the nearest…?). The student who has the card with the answer to the question on it must answer (I have…), then read the question on their card.
Continue the game until you return to the first question.
Source: translated from Guide d'enseignement efficace des mathématiques de la 4e à la 6e année, Numération et sens du nombre, Fascicule 1, Nombres naturels, p. 190.
Activity 2: Rounding Whole Numbers According to the Context
Present the following situation to students:
A class from Horizon School went to the orchard to pick apples. They picked 8815 grams of apples. The students would like to write an article about this in the next edition of the school newspaper.
Ask students questions such as:
- In this situation, should the number be rounded? Why or why not?
- Should the number be rounded up or down? Explain your reasoning.
- Do you think students should round up to the nearest ten, hundred, or thousand when writing their article? Justify your answer.
- What do you notice when you round the number to the nearest 10? To the nearest hundred? To the nearest thousand? How do you know?