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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 848 · 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. 1.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  2. 2.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?
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  5. 5.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  7. 7.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  8. 8.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?
  9. 9.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?
  10. 10.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  11. 11.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  12. 12.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?
  13. 13.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?
  14. 14.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  15. 15.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  16. 16.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  19. 19.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  20. 20.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.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?
  22. 22.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  23. 23.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?
  24. 24.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  25. 25.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  26. 26.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  27. 27.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  29. 29.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?
  30. 30.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  32. 32.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  33. 33.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  34. 34.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?
  35. 35.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?
  36. 36.A leapfrog list starts 5, 6 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): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  38. 38.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  39. 39.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?

Answer key

  1. 627
  2. 1089
  3. 253
  4. 759
  5. 253
  6. 308
  7. 715
  8. 1001
  9. 957
  10. 847
  11. 671
  12. 462
  13. 880
  14. 308
  15. 550
  16. 759
  17. 561
  18. 561
  19. 583
  20. 484
  21. 968
  22. 649
  23. 429
  24. 495
  25. 583
  26. 396
  27. 1199
  28. 638
  29. 341
  30. 1001
  31. 396
  32. 429
  33. 583
  34. 968
  35. 847
  36. 803
  37. 528
  38. 759
  39. 660
  40. 759

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