Question 10 of 22intermediate🔍 AnalyzeShort Answer4 marks

Whenever Jasoda has to subtract 9 from a number, she subtracts 10 and adds 1 to it. For example, 36 - 9 = 26 + 1. (a) Do you think she always gets the correct answer? Why? (b) Can you think of other similar strategies? Give some examples.

(a)
Answer

Yes, she always gets the correct answer because subtracting 9 equals subtracting 10 and adding 1. This works because 9 = 10 - 1.

(b)
Answer

To subtract 8: subtract 10, add 2. To subtract 19: subtract 20, add 1. To subtract 99: subtract 100, add 1.

Explanation

(a) The mathematical basis is: n - 9 = n - 10 + 1, since -9 = -10 + 1 (b) These strategies work by adjusting to convenient round numbers and compensating.

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