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 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 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?
- 3.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 4.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?
- 5.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 6.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?
- 7.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 8.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 9.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 10.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 11.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 12.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 13.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?
- 14.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.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?
- 16.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 17.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?
- 18.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?
- 19.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 20.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?
- 21.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 22.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?
- 23.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?
- 24.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 25.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 27.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?
- 28.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 29.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 30.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 31.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 32.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 33.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 34.A leapfrog list starts 6, 4 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): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 37.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 38.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 40.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
Answer key
- 594
- 1001
- 583
- 451
- 682
- 869
- 198
- 429
- 781
- 979
- 1034
- 341
- 649
- 495
- 550
- 1287
- 957
- 198
- 957
- 847
- 671
- 539
- 935
- 660
- 726
- 616
- 231
- 1199
- 143
- 484
- 924
- 671
- 979
- 682
- 451
- 1034
- 704
- 572
- 1177
- 374
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