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 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 2.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 3.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 4.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 5.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?
- 6.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 8.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?
- 9.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 12.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 13.A leapfrog list starts 6, 6 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): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 15.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?
- 16.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?
- 17.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.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?
- 19.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 20.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 21.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 22.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 23.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?
- 24.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 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): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 27.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 28.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?
- 29.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 30.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 31.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 32.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 33.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 34.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 36.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?
- 37.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?
- 38.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 39.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 40.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
Answer key
- 759
- 1177
- 1023
- 671
- 1144
- 979
- 693
- 891
- 1089
- 1287
- 583
- 1232
- 858
- 561
- 1122
- 231
- 1232
- 847
- 803
- 561
- 143
- 550
- 319
- 946
- 583
- 880
- 506
- 484
- 814
- 825
- 539
- 418
- 341
- 924
- 891
- 550
- 539
- 374
- 715
- 1034
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