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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 534 · 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. 1.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  2. 2.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  4. 4.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?
  5. 5.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  6. 6.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?
  7. 7.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?
  8. 8.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  10. 10.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  11. 11.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?
  12. 12.A leapfrog list starts 6, 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 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  18. 18.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  21. 21.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  22. 22.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?
  23. 23.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  26. 26.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  28. 28.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  29. 29.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  30. 30.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?
  31. 31.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  32. 32.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  35. 35.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?
  36. 36.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  40. 40.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?

Answer key

  1. 1089
  2. 858
  3. 594
  4. 968
  5. 374
  6. 1089
  7. 341
  8. 924
  9. 594
  10. 231
  11. 638
  12. 506
  13. 363
  14. 198
  15. 319
  16. 286
  17. 143
  18. 143
  19. 869
  20. 1287
  21. 1001
  22. 924
  23. 891
  24. 286
  25. 231
  26. 418
  27. 506
  28. 649
  29. 946
  30. 495
  31. 847
  32. 671
  33. 253
  34. 462
  35. 451
  36. 308
  37. 660
  38. 539
  39. 715
  40. 451

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