Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 795 · 40 questions

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.

1. 1.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
2. 2.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
3. 3.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
4. 4.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
5. 5.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
6. 6.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
7. 7.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
8. 8.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
9. 9.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
10. 10.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
11. 11.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?
12. 12.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?
13. 13.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?
14. 14.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
15. 15.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
16. 16.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
17. 17.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?
18. 18.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?
19. 19.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
20. 20.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
21. 21.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
22. 22.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
23. 23.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?
24. 24.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
25. 25.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?
26. 26.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
27. 27.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
28. 28.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
29. 29.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
30. 30.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?
31. 31.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?
32. 32.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
33. 33.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
34. 34.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
35. 35.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?
36. 36.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?
37. 37.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
38. 38.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?
39. 39.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
40. 40.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

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