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Mathemania

Mathemania. Math 170 – Chapter 3 and 4. Misc Mental Math. Add. Subtract. Multiply. Divide. 10. 10. 10. 10. 10. 20. 20. 20. 20. 20. 30. 30. 30. 30. 30. 40. 40. 40. 40. 40. 50. 50. 50. 50. FINAL. Addition. 10 Point Question.

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Mathemania

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  1. Mathemania Math 170 – Chapter 3 and 4 Misc Mental Math Add Subtract Multiply Divide 10 10 10 10 10 20 20 20 20 20 30 30 30 30 30 40 40 40 40 40 50 50 50 50 FINAL

  2. Addition

  3. 10 Point Question Sketch which base 5 pieces you would need to represent 10235? one long-flat, two longs, three units. Check Work Go Home

  4. 20 Point Question Rewrite 3+(2+6) using only the commutative property of addition once. 3+(6+2) or (2+6)+3 Check Work Go Home

  5. 30 Point Question Use only the associative property of addition to rewrite 3+(6+2). (3+6)+2 Check Work Go Home

  6. 40 Point Question Add the following: 2335 +1435 4315 Check Work Go Home

  7. 50 Point Question Explain how to mentally compute 237 + 140 + 23 Add the 237 and 23 first to get a sum of 260. Then add in the 140 to get a total of 500. Check Work Go Home

  8. Subtraction

  9. 10 Point Question Two models for subtraction are the comparison concept and the missing addend concept. What is the third model? The take-away concept. Check Work Go Home

  10. 20 Point Question Show, with base-5 pieces 215 – 145. Start with two longs and one unit. Since you can’t remove 4 units, trade a long for 5 units, then remove 4. Finally remove a long. You should be left with just 2 units. Check Work Go Home

  11. 30 Point Question Harry has $2500 in cash to pay for a secondhand car, or he can pay $500 down and $115 per month for 2 years. If he doesn’t pay the full amount in cash, he can invest the difference and make $150. How much money will he lose if he chooses the more expensive option? $3370 on the payment plan Check Work Go Home

  12. 40 Point Question How can the comparison model for subtraction be used to compute 34 – 29? 34 is 5 more than 29, so 34 – 29 = 5. Check Work Go Home

  13. 50 Point Question How does the take away model for subtraction apply to the problem 43-12? If you have 43 objects and someone takes away 12, you will be left with 31. So 43 – 12 = 31 Check Work Go Home

  14. Multiplication

  15. 10 Point Question Which property of multiplication is illustrated below? 1.a = a.1 = a The identity property of multiplication Check Work Go Home

  16. 20 Point Question Find the product 135 and 325 10215 Check Work Go Home

  17. 30 Point Question Draw an array showing 23 x 14. How many squares are enclosed? 23 rows and 14 columns (or 14 rows and 23 columns.) for a total of 322 Check Work Go Home

  18. 40 Point Question A store carries five styles of backpacks in four different sizes. The customer also has a choice of two different kinds of material. How many different choices does a customer have? 40 Check Work Go Home

  19. 50 Point Question Multiplying a 4 digit number by this number is easy: just write the 4 digit number down twice in a row. What is the number? 10001 Check Work Go Home

  20. Division

  21. 10 Point Question What are the three models for division? Missing factor, sharing (partitive) and measurement (subtractive.) Check Work Go Home

  22. 20 Point Question Sketch two ways to divide 48 by 8. Either 6 groups of 8 (measurement) or 8 groups of 6 (sharing/partitive) Check Work Go Home

  23. 30 Point Question Use sketches of base 5 pieces to show 142five divided by 11five. Start with a flat, 4 longs and 2 units. Divide them into 6 groups. There will be 1 long and 2 units in each group, with 1 long left over. (So the answer is 12five with a remainder of 10five. Check Work Go Home

  24. 40 Point Question Evaluate 1440/12X10+18 1218 Check Work Go Home

  25. 50 Point Question Find the quotient of 4052 and 8. (Using whole number division.) 506 R 4 Check Work Go Home

  26. Mental Math

  27. 10 Point Question Which two numbers are compatible for addition? 42, 37, 81, 55, 24, 33 37 and 33 Check Work Go Home

  28. 20 Point Question Explain how to do the following problem using mental math. 21X36 + 21X64 Use the distributative property to make it 21X(36+64) Add the compatible numbers, then multiply to get 2100. Check Work Go Home

  29. 30 Point Question Use the range method to get estimates for 236+153. Low: 300, high 500. Check Work Go Home

  30. 40 Point Question Explain how to use the compensation method to find 248+296. I would take 4 from the 248 and add it to the 296 so the sum becomes 244 + 300 = 544. I guess you could also take 2 from the 296 and add it to the 248 so the problem becomes 250 + 294, but my way results in an easier sum. Check Work Go Home

  31. Final Question In the standard multiplication algorithm, why do we “shift over one to the left” as illustrated in the 642 in the following problem? 321 X 23 963 +642 Ooh. Good question. Maybe I’ll put this one on the test. Check Work Go Home

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