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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 317 · 40 questions
TalentJR

The trick (Seventh times eleven): A leapfrog list: start with two numbers, then each number is the sum of the two before it, up to 10 numbers. Find the 7th number. Multiply it by 11 (the number with a 0 on the end, plus the number): that is the total of all 10.

NameDateTime takenScore ___ / 40
  1. 1.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  3. 3.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  4. 4.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  6. 6.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  10. 10.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  11. 11.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  12. 12.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  13. 13.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  14. 14.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  15. 15.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  17. 17.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  18. 18.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  19. 19.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  20. 20.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  25. 25.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  27. 27.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  28. 28.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  32. 32.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  33. 33.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  34. 34.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  36. 36.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  37. 37.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  39. 39.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?

Answer key

  1. 473
  2. 396
  3. 836
  4. 341
  5. 1001
  6. 781
  7. 913
  8. 935
  9. 407
  10. 495
  11. 935
  12. 473
  13. 693
  14. 528
  15. 517
  16. 341
  17. 1287
  18. 957
  19. 869
  20. 1012
  21. 319
  22. 1089
  23. 924
  24. 847
  25. 407
  26. 616
  27. 583
  28. 759
  29. 869
  30. 847
  31. 737
  32. 572
  33. 726
  34. 451
  35. 374
  36. 638
  37. 759
  38. 1111
  39. 594
  40. 968

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