Peter’s Way 21 x 24 400 + 100 500 Teacher Note: While Peter was constructing his array model, he forgot to multiply the ones place value times the ones place value. There should be 4 ones (red cubes) on the bottom right corner of his model. He would have then counted his 4 hundreds, 10 tens, and 4 ones. He would have then had 400+100+4=504 21 x 24 = 500

This doesn’t look right. Carlos’ Math 37 x 43 Uh-oh! This doesn’t look right. 40 3 120 90 280 + 21 511 30 x 40 120 30 x 3 90 30 7 7 x 40 280 7 x 3 21 Teacher Note: Carlos’ mistake is in the upper left box of the area model where he multiplied 30x40. The answer should have been 1,200 instead of 120 which them led to his final answer being incorrect. This student most likely is having difficulties with multiplying by 10’s. The correct answer is 30x40=1,200, 30x3=90, 7x40=280, 7x3=21; 1,200+90+280+21=1,591; 37x43=1,591 37 x 43 = 511

Ashley’s Work 59 x 13 = 667 59 x 13 59 x 13 27 -> 3x9 Teacher Note: Ashley understands her multiplication using place values but made a small mistake when adding. When she added the tens, she got 16 tens but forgot to carry over 1 into the hundreds to make it 6 hundreds. The correct answer is 59x13=767

Nina’s Strategy I think I did it! 53 x 38 53 x 38 424 + 159 583 Teacher Note: Nina struggles with understanding the place value of the digit 3 in 38. She sees it as a “3” rather than a “30” There should be a zero to the right of 159 making it 1,590. It should say 424+1,590=2,014 53 x 38 = 583

Erika’s Thoughts 29 x 67 (20 + 9) x (60 + 7) I need help with this 29 x 67 (20 + 9) x (60 + 7) (20x60)+(20x7)+(9x60)+(9x7) 1200 + 140 + 450 + 63 1340 + 513 1,853 Teacher Note: This student understands the distributive property and how it relates to multiplication clearly. However, she made a simple mistake when multiplying 9x60. She said that 9x60=450 when it should be 9x60=540. She would have then been able to give the correct answer of 29x67=1,943. 29 x 67 = 1,853