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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 681 · 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 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  4. 4.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?
  5. 5.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.A leapfrog list starts 7, 2 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 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  9. 9.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?
  10. 10.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  11. 11.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  12. 12.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  13. 13.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  14. 14.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?
  15. 15.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  16. 16.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  17. 17.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  18. 18.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  20. 20.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?
  21. 21.A leapfrog list starts 4, 4 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 8, 6 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 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  26. 26.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  27. 27.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  28. 28.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  30. 30.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?
  31. 31.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  33. 33.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  35. 35.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  36. 36.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  38. 38.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  39. 39.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  40. 40.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?

Answer key

  1. 693
  2. 605
  3. 418
  4. 506
  5. 880
  6. 561
  7. 143
  8. 1232
  9. 1287
  10. 858
  11. 1067
  12. 759
  13. 517
  14. 253
  15. 1122
  16. 946
  17. 627
  18. 759
  19. 847
  20. 1089
  21. 572
  22. 968
  23. 946
  24. 737
  25. 660
  26. 561
  27. 671
  28. 902
  29. 649
  30. 495
  31. 836
  32. 286
  33. 1232
  34. 627
  35. 847
  36. 198
  37. 1012
  38. 605
  39. 968
  40. 638

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