Question 1: Calculate 345 - 127 using exchanging method. Show each step.

Answer: 218

Question 2: Subtract 462 from 725 by exchanging hundreds and tens. Show your working.

Answer: 263

Question 3: In a calculation, 508 - 269, identify where exchanging occurs and explain why.

Answer: Exchanging occurs when 8 in the units place is less than 9 in the minuend, so 1 ten is borrowed, making the units 18. This allows subtraction without borrowing further.

Question 4: Solve 629 - 385 by exchanging tens and hundreds. Show your steps.

Answer: 244

Question 5: A shop has 834 pens. If 296 pens are sold, how many are left? Use exchanging in your subtraction.

Answer: 538

Question 6: Subtract 473 from 682, demonstrating the exchanging process.

Answer: 209

Question 7: Explain what happens during exchanging when subtracting 714 - 389.

Answer: When subtracting, if the units digit of the subtrahend is larger than the minuend's units digit, borrowing (exchanging) occurs by taking 1 ten from the tens place, converting it into 10 units, to perform the subtraction.

Question 8: Estimate and then accurately calculate 950 - 378, showing the exchanging steps.

Answer: 572

Question 9: A factory produces 1,243 units in one day. If 789 units are defective and discarded, how many units are acceptable? Use exchanging in subtraction.

Answer: 454

Question 10: A calculator displays an error when subtracting 563 - 278. Explain the common mistake students make with exchanging and how to correct it.

Answer: A common mistake is forgetting to borrow when the units digit of the subtrahend is larger than that of the minuend. To correct it, ensure to borrow 1 ten from the tens place, converting it into 10 units, and then proceed with subtraction.

Question 11: Challenge: Subtract 832 - 479 using exchanging, then verify your answer by addition.

Answer: 353