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
- 1.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 2.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?
- 3.A leapfrog list starts 9, 4 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): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 5.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?
- 6.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 7.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?
- 8.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 9.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 10.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 11.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 12.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 13.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?
- 14.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 15.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 16.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?
- 17.A leapfrog list starts 1, 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 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 20.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 22.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 23.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 24.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?
- 25.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?
- 26.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?
- 27.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?
- 28.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 29.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.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?
- 31.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?
- 32.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 33.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 34.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 35.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 36.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 37.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 38.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
- 39.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 40.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?
Answer key
- 935
- 935
- 847
- 319
- 231
- 880
- 913
- 836
- 396
- 759
- 1144
- 473
- 814
- 495
- 671
- 451
- 847
- 308
- 418
- 341
- 550
- 429
- 143
- 649
- 1177
- 1177
- 1056
- 506
- 473
- 583
- 616
- 924
- 462
- 660
- 792
- 946
- 1012
- 946
- 770
- 198
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