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
- 1.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 2.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 3.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?
- 4.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 5.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 6.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 7.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.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?
- 9.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?
- 10.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 11.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?
- 12.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 13.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 14.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 15.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?
- 16.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 17.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?
- 18.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?
- 19.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 20.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?
- 21.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 22.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 23.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 24.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 25.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 26.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?
- 27.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 28.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 29.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 30.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?
- 31.A leapfrog list starts 3, 8 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 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.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?
- 34.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 35.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?
- 36.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 37.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 38.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?
- 39.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?
- 40.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
Answer key
- 396
- 1034
- 880
- 836
- 847
- 1012
- 1111
- 605
- 451
- 836
- 484
- 792
- 726
- 1111
- 539
- 781
- 638
- 902
- 1122
- 671
- 231
- 638
- 968
- 715
- 363
- 1089
- 407
- 649
- 341
- 891
- 869
- 1122
- 1144
- 902
- 583
- 616
- 539
- 1001
- 726
- 869
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