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
- 1.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 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?
- 3.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 4.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?
- 5.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 6.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?
- 7.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 8.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?
- 9.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?
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 12.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?
- 13.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 14.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?
- 15.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?
- 16.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?
- 17.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?
- 18.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 19.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.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?
- 21.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?
- 22.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 23.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 25.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?
- 26.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 27.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 29.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?
- 30.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 31.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 32.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 33.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 35.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?
- 36.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?
- 37.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?
- 38.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 39.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?
- 40.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 418
- 517
- 506
- 737
- 792
- 825
- 363
- 1012
- 880
- 968
- 451
- 1001
- 1144
- 396
- 1144
- 759
- 528
- 572
- 891
- 968
- 671
- 1067
- 814
- 759
- 605
- 704
- 583
- 341
- 583
- 781
- 473
- 781
- 770
- 1023
- 462
- 484
- 759
- 1089
- 869
- 143
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