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.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?
- 3.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 4.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 5.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 6.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?
- 7.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?
- 8.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 9.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 11.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?
- 12.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 13.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 16.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?
- 17.A leapfrog list starts 7, 9 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 8, 3 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): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 20.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 21.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 22.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?
- 23.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 24.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 25.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?
- 26.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?
- 27.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?
- 28.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 29.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
- 30.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?
- 31.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 32.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?
- 33.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 34.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 35.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.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?
- 37.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 38.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 39.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 40.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 880
- 1001
- 583
- 484
- 418
- 759
- 715
- 429
- 671
- 1034
- 671
- 517
- 1034
- 913
- 803
- 484
- 1177
- 704
- 913
- 198
- 715
- 649
- 374
- 1056
- 583
- 1199
- 539
- 825
- 1177
- 341
- 891
- 528
- 231
- 847
- 1001
- 869
- 924
- 1067
- 286
- 957
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