Question 1 - Figure it out - Page 93, 94 - Chapter 4 Class 7 - Expressions using Letter-Numbers (Ganita Prakash)

Transcript

Question 1 Add the numbers in each picture below. Write their corresponding expressions and simplify them. Try adding the numbers in each picture in a couple different ways and see that you get the same thing.Okay let’s answer one by one Image 1 Adding row wise Sum = (5y – 6 + x) + (x + 2 + 5y) = (5y + 5y) + (x + x) + (–6 + 2) = 10y + 2x – (6 – 2) = 10y + 2x – 4 Adding column wise Sum = (5y + x) + (–6 + 2) + (x + 5y) = (5y + 5y) + (x + x) + (–6 + 2) = 10y + 2x – (6 – 2) = 10y + 2x – 4 Image 2 = 8p + 12q + 3 + 3 – (2 + 2) = 8p + 12q + 6 – 4 = 8p + 12q + 2 Image 3 Adding row wise Sum = (–5g + 5k + 5k – 5g) + (5k + 5k + 5k + 5k) + (5k + 5k + 5k + 5k) + (–5g + 5k + 5k – 5g) = (5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k ) + (-5g – 5g – 5g – 5g) = (5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k ) – (5g + 5g + 5g + 5g) = 12 × 5k – 4 × 5g = 60k – 20g Adding column wise Sum = (–5g + 5k + 5k – 5g) + (5k + 5k + 5k + 5k) + (5k + 5k + 5k + 5k) + (–5g + 5k + 5k – 5g) = (5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k ) + (-5g – 5g – 5g – 5g) = (5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k ) – (5g + 5g + 5g + 5g) = 12 × 5k – 4 × 5g = 60k – 20g Adding row wise Sum = (2p + 3q – 2 + 3) + (3q + 2p + 3 – 2) + (2p + 3q) + (3q + 2p) = (2p + 2p + 2p + 2p) + (3q + 3q + 3q + 3q) + (3 + 3 – 2 – 2) = 8p + 12q + 3 + 3 – (2 + 2) = 8p + 12q + 6 – 4 = 8p + 12q + 2 Adding column wise Sum = (2p + 3q) + (3q + 2p) + (–2 + 3 + 2p + 3q) + (3 – 2 + 3q + 2p) = (2p + 2p + 2p + 2p) + (3q + 3q + 3q + 3q) + (3 + 3 – 2 – 2)