Question 5 (a) - Figure it out (Page 42, 43, 44) - Chapter 2 Class 7 - Arithmetic Expressions (Ganita Prakash)

Transcript

Question 5 (a) Identify which of the following expressions are equal to the given expression without computation. You may rewrite the expressions using terms or removing brackets. There can be more than one expression which is equal to the given expression. (a) 83 – 37 – 12 (i) 84 – 38 – 12 (ii) 84 – (37 + 12) (iii) 83 – 38 – 13 (iv) – 37 + 83 –12 (i) 84 – 38 – 12 Let’s look individual numbers 84 vs 83 - It is +1 38 vs 37 – so its subtracting 1 more 12 vs 12 – it is same Thus, it is the same expression (ii) 84 – (37 + 12) We rewrite it as 84 – 37 – 12 Let’s look individual numbers 84 vs 83 – It is +1 37 vs 37 – it is same 12 vs 12 – it is same Thus, it is not same expression, as it has 1 more (iii) 83 – 38 – 13 Let’s look individual numbers 84 vs 83 – It is +1 38 vs 37 – so its subtracting 1 more 12 vs 12 – so its subtracting 1 more Thus, it is not same expression, as it has 2 less (iv) – 37 + 83 – 12 We rewrite it as 83 – 37 – 12 This is the same expression