Leapfrog Sum Trick Worksheet
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
- 1.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 2.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?
- 3.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 4.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 5.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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?
- 7.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 8.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 9.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?
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 12.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?
- 13.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 14.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 15.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 16.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?
- 17.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?
- 18.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 19.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?
- 20.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?
- 21.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 22.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 23.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 24.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 25.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 26.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 27.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.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?
- 30.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?
- 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 32.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 33.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?
- 34.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?
- 35.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?
- 36.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 37.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 39.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?
- 40.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
Answer key
- 979
- 143
- 253
- 473
- 517
- 231
- 418
- 363
- 1012
- 308
- 550
- 902
- 726
- 286
- 946
- 495
- 847
- 880
- 627
- 726
- 231
- 396
- 704
- 858
- 979
- 462
- 759
- 792
- 715
- 198
- 616
- 550
- 737
- 462
- 693
- 1023
- 781
- 759
- 803
- 539
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