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 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 2.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?
- 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, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 5.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 6.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 7.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 8.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?
- 9.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 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?
- 11.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 12.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 13.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 14.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 15.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 18.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 19.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?
- 20.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 21.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?
- 22.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?
- 23.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.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?
- 25.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?
- 26.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 27.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?
- 28.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 29.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 30.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?
- 31.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 32.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 34.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?
- 35.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 36.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?
- 37.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?
- 38.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 39.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?
- 40.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?
Answer key
- 704
- 143
- 847
- 847
- 781
- 253
- 396
- 539
- 935
- 1287
- 550
- 572
- 825
- 308
- 1023
- 253
- 858
- 957
- 1001
- 1089
- 528
- 1177
- 638
- 715
- 902
- 583
- 671
- 198
- 319
- 319
- 363
- 803
- 253
- 198
- 451
- 1199
- 517
- 1111
- 924
- 561
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