Question 1: Calculate 87 - 29 using mental strategies.

Answer: 58

Question 2: Subtract 46 from 73 mentally. Describe your strategy.

Answer: Break 73 into 70 and 3, then subtract 46 from 70 (which is 24), and add back the 3, giving 27.

Question 3: Calculate 94 - 58 mentally by rounding.

Answer: 36

Question 4: Solve 65 - 27 using mental subtraction with complementary numbers.

Answer: 38

Question 5: Subtract 33 from 58 mentally. Explain your method.

Answer: Subtract 30 to get 28, then subtract 3 to get 25.

Question 6: Calculate 99 - 72 using near-doubles.

Answer: 27

Question 7: A shop has 86 items. If 29 items are sold, how many are left? Use mental subtraction.

Answer: 57

Question 8: Calculate 74 - 59 mentally by decomposing 59.

Answer: 15

Question 9: Estimate 83 - 46 mentally and then check the exact answer.

Answer: Approximate: 80 - 50 = 30; Exact: 83 - 46 = 37

Question 10: Identify and correct the mistake: Subtract 65 - 38 by taking 65 - 30 = 35, then subtracting 8 to get 27.

Answer: Incorrect. Subtracting 8 from 65 after subtracting 30 does not account for the remaining 8 properly. Correct approach: subtract 38 from 65 by breaking 38 into 30 and 8; 65 - 30 = 35, then 35 - 8 = 27. The method is correct but needs careful handling of the subtraction steps.