Question 2 - Mind the Mistake, Mend the Mistake - Chapter 7 Class 7 - Finding the Unknown (Ganita Prakash II)

Transcript

Question 2 The following are some equations along with the steps used to solve them to find the value of the letter−number. Go through each solution and decide whether the steps are correct. If there is a mistake, describe the mistake, correct it and solve the equation.Is there a mistake? Yes What went wrong? In the last step (8z = 2), the student divided incorrectly. They thought z = 8 ÷ 2, but to get z alone, you have to divide by the number attached to it (which is 8). Correct solution Now, 7 – 8z = 5 Taking 7 on right side, it becomes subtraction –8z = 5 – 7 –8z = –7 + 5 –8z = –(7 – 5) –8z = –2 Cancelling negative sign 8z = 2 Taking 8 on right side, it becomes division z = 𝟐/𝟖 z = 𝟏/𝟒