Question 1: Calculate: rac{3}{4} - rac{1}{2}.

Answer: 1/4

Question 2: Calculate: rac{5}{6} - rac{1}{3}.

Answer: 1/2

Question 3: Calculate: rac{7}{8} - rac{2}{5}.

Answer: 11/40

Question 4: Calculate: rac{9}{10} - rac{3}{4}.

Answer: 3/20

Question 5: Calculate: rac{2}{3} - rac{1}{6}.

Answer: 1/2

Question 6: Calculate: rac{4}{9} - rac{2}{3}.

Answer: -2/9

Question 7: A recipe requires rac{5}{8} cups of flour. If you already added rac{1}{2} cups, how much more do you need to add? (Subtract the amounts.)

Answer: 1/8

Question 8: A student has rac{7}{10} meters of ribbon. They cut off rac{2}{5} meters. How much ribbon remains?

Answer: 1/2

Question 9: Plot the graph of y = rac{1}{2}x on the grid. Draw the line for x values from 0 to 10.

Answer: Line plotting from (0,0) to (10,5)

Question 10: Construct a triangle with sides rac{3}{4}, rac{2}{3}, and rac{5}{6}. Use the grid for accuracy.

Answer: Constructed triangle with approximate side lengths matching fractions

Question 11: Calculate: rac{11}{15} - rac{3}{5}.

Answer: 2/15

Question 12: Identify and correct the mistake in this subtraction: rac{3}{4} - rac{2}{3} = rac{1}{12}.

Answer: Incorrect; common denominator is 12, subtract numerators (9 - 8 = 1), result is rac{1}{12} which is correct, so the mistake is in the initial calculation or understanding.