Unit
1
Facilitator’s Guide G04 ~ Mathematics
Example: Study number sentence: 9 – 2 = We are not going to draw any pictures to solve this number sentence. Use mental maths and decide on an answer. You will then see – by using inspection – that the answer is 7.
ACTIVITY 7 1.
Solve the number sentences using inspection. 1.1 1.2 1.3 1.4 1.5
Question
Answer
273 + 6 =
279
42 – 12 =
30
67
62 + 5 =
964
997 – 33 =
42
54 – 12 =
Now let us look at the solving of number sentences through the trial and improvement method.
Using this method, you will guess an answer, but you will write it down and then calculate the number
sentence. If your answer is not correct, you can try another answer and calculate the number sentence until it is correct or until the number sentence is TRUE. This number sentence is FALSE:
This number sentence is TRUE:
413 – 2 = 410
413 – 2 = 411
Example: Study the number sentence below and use the trial and improvement method to solve it. 156 –
= 149
Attempt 1: Guess an answer that will make the number sentence TRUE. Guess that a 6 in the block will make the number sentence true.
156 – 6 = 149
© Impaq
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