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
- 1.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 2.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 3.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?
- 4.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 5.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 7.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 8.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 9.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 12.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 13.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 14.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?
- 15.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?
- 16.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?
- 17.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 18.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?
- 19.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 20.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 21.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 22.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 23.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 24.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?
- 25.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 26.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 27.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 29.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?
- 30.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 31.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?
- 32.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 34.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?
- 35.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?
- 36.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?
- 37.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 38.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?
- 39.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.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?
Answer key
- 605
- 517
- 561
- 693
- 286
- 341
- 407
- 1034
- 649
- 605
- 583
- 253
- 704
- 429
- 484
- 539
- 671
- 759
- 363
- 616
- 616
- 726
- 1144
- 847
- 814
- 484
- 550
- 1111
- 484
- 803
- 495
- 715
- 506
- 759
- 935
- 924
- 825
- 1012
- 451
- 902
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