1 minute read
LESSON 2: NUMBER SENTENCES
Self-assessment
Do you understand the work? Colour the faces that show what you can do.
REPRESENTING WHOLE NUMBERS Requirements
I can represent whole numbers in different ways.
I know the difference between even and odd numbers.
I can round off numbers to the nearest 5, 10, 100 and 1 000. Can I do it?
You studied number sentences in Grade 4. In Grade 5, you will use number sentences to describe problems and solve number sentences through inspection and by trial and improvement.
Briefly revise the Grade 4 work.
What are number sentences?
A number sentence is an arrangement of numbers and symbols:
You will not always work with number sentences. Sometimes a maths problem is expressed in words, and before you can solve it mathematically, you must first formulate a number sentence.
Example: Your swimming lessons cost R3 900. Your mom makes 12 equal payments. How much is each payment?
Start by reading the problem again and writing down the information:
Total amount for lessons: R3 900 How many payments? 12 equal payments
The question does not ask how much your mom paid in total, but how much she must pay each month (12 payments). Write down the number sentence:
3 900 ÷ 12 = ?
Apply your Grade 4 calculation skills:
. 3 2 5 1 2 3 9 0 0 - 3 6 3 0 - 2 4 6 0 - 6 0 0
It means that your mother must make 12 equal payments of R325 each.
In this number sentence, we divided numbers.
You can also write a number sentence with – , + , × and ÷.
Example: Melanie has 36 blue marbles and Refilwe has 25 red marbles and 17 blue marbles. How many blue marbles do they have altogether?
36 + 17 = ?
If we want to solve the number sentence:
36 + 17 = 53
Melanie and Refilwe have 53 blue marbles altogether.
Write a few of your own number sentences.
