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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 708 · 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 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  4. 4.A leapfrog list starts 9, 5 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): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  6. 6.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  7. 7.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  9. 9.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  10. 10.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  11. 11.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  17. 17.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  19. 19.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?
  20. 20.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?
  21. 21.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  22. 22.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  23. 23.A leapfrog list starts 2, 1 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): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  25. 25.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  30. 30.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?
  31. 31.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  33. 33.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?
  34. 34.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  35. 35.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  37. 37.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  38. 38.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  39. 39.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =

Answer key

  1. 968
  2. 869
  3. 286
  4. 935
  5. 1067
  6. 946
  7. 924
  8. 671
  9. 594
  10. 319
  11. 341
  12. 231
  13. 935
  14. 319
  15. 253
  16. 1111
  17. 396
  18. 880
  19. 638
  20. 253
  21. 495
  22. 638
  23. 198
  24. 957
  25. 770
  26. 1012
  27. 605
  28. 649
  29. 374
  30. 594
  31. 957
  32. 1232
  33. 671
  34. 671
  35. 396
  36. 759
  37. 1001
  38. 792
  39. 1144
  40. 737

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