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
- 1.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 2.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 3.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 4.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.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?
- 6.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?
- 7.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 8.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 9.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?
- 10.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?
- 11.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?
- 12.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?
- 13.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?
- 14.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 15.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?
- 16.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 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.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.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?
- 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?
- 21.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 22.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?
- 23.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 24.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
- 25.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?
- 26.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 27.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?
- 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.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.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?
- 32.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 33.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 34.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 35.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 36.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 37.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 38.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 39.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 40.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
Answer key
- 880
- 198
- 319
- 649
- 550
- 869
- 781
- 682
- 429
- 1122
- 704
- 737
- 759
- 407
- 1199
- 396
- 462
- 1067
- 781
- 671
- 671
- 539
- 847
- 1232
- 231
- 759
- 902
- 792
- 671
- 506
- 517
- 396
- 506
- 671
- 605
- 1144
- 374
- 451
- 198
- 1056
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