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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 426 · 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 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  4. 4.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.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?
  7. 7.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  10. 10.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  14. 14.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  16. 16.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  18. 18.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  21. 21.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  23. 23.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  25. 25.A leapfrog list starts 2, 6 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, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  28. 28.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  29. 29.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  30. 30.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  32. 32.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  34. 34.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  35. 35.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  37. 37.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  38. 38.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  39. 39.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?

Answer key

  1. 407
  2. 847
  3. 1056
  4. 913
  5. 1056
  6. 935
  7. 649
  8. 539
  9. 660
  10. 869
  11. 462
  12. 616
  13. 1067
  14. 594
  15. 1144
  16. 649
  17. 429
  18. 1287
  19. 1023
  20. 693
  21. 1012
  22. 770
  23. 495
  24. 869
  25. 638
  26. 528
  27. 1089
  28. 253
  29. 814
  30. 770
  31. 902
  32. 550
  33. 671
  34. 913
  35. 374
  36. 825
  37. 1034
  38. 924
  39. 715
  40. 682

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