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 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 2.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?
- 3.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 4.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?
- 5.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 6.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?
- 7.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 8.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 9.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 10.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 11.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?
- 12.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 13.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 14.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?
- 15.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?
- 16.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 17.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 18.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 19.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 20.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?
- 21.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 22.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 23.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 24.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?
- 25.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 26.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?
- 27.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?
- 28.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 29.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?
- 30.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 31.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 32.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 33.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 34.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 35.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?
- 36.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?
- 37.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 38.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?
- 39.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?
- 40.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
Answer key
- 682
- 231
- 231
- 506
- 891
- 462
- 253
- 319
- 616
- 814
- 869
- 1089
- 627
- 583
- 759
- 814
- 1287
- 803
- 1144
- 913
- 539
- 407
- 561
- 1111
- 550
- 649
- 528
- 1067
- 946
- 847
- 759
- 1034
- 649
- 1287
- 484
- 198
- 286
- 462
- 616
- 418
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