Question 1: Calculate mentally: 46 + 27.

Answer: 73

Question 2: Add 58 and 37 using a mental shortcut. Show your reasoning.

Answer: 58 + 37 = (58 + 2) + 35 = 60 + 35 = 95

Question 3: Estimate the sum of 49 and 52 by rounding to the nearest ten before adding.

Answer: 50 + 50 = 100

Question 4: Add 63 and 29 by breaking down numbers into tens and ones.

Answer: 63 + 29 = (60 + 3) + (20 + 9) = (60 + 20) + (3 + 9) = 80 + 12 = 92

Question 5: A student incorrectly adds 56 and 27 by doing 50 + 20 + 6 + 7. Identify the mistake and correct it.

Answer: The student added the hundreds and tens separately, but since 56 is not a multiple of ten, they missed the proper place value. Correct addition: 56 + 27 = 83.

Question 6: Add 44 and 38 using a mental strategy involving compatible numbers.

Answer: 44 + 38 = (44 + 6) + 32 = 50 + 32 = 82

Question 7: A problem: You have 47 apples and get 26 more. How many apples do you have in total? Solve mentally and explain your strategy.

Answer: 47 + 26 = (47 + 3) + 23 = 50 + 23 = 73

Question 8: Add 65 and 27. Use a mental strategy involving rounding to the nearest ten and adjusting.

Answer: 65 + 27 = 65 + 30 - 3 = 95 - 3 = 92

Question 9: Challenge: Without calculating directly, estimate the sum of 89 and 76 by rounding to the nearest ten and then adjusting.

Answer: 90 + 80 = 170; since 89 and 76 are just below these, estimate around 165

Question 10: Identify the common mistake when adding 68 and 27 mentally and correct the sum.

Answer: Common mistake: adding 60 + 20 + 8 + 7 without combining properly. Correct sum: 68 + 27 = 95.

Question 11: Plot the graph of y=2x for x from 0 to 10 on the grid.

Answer: Student draws the line y=2x passing through points (0,0), (1,2), (2,4), ..., (10,20).