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.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?
- 2.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 3.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 4.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 5.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 6.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 7.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
- 8.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 9.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 10.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?
- 11.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?
- 12.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.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?
- 14.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 15.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 16.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 17.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?
- 18.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 19.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.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?
- 21.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 22.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?
- 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?
- 24.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 25.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?
- 26.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 27.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 28.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 29.A leapfrog list starts 6, 8 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): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
- 31.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 32.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.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?
- 34.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 35.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 36.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 38.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 40.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
Answer key
- 979
- 429
- 924
- 858
- 671
- 869
- 429
- 836
- 759
- 374
- 671
- 792
- 484
- 726
- 341
- 605
- 814
- 407
- 660
- 253
- 473
- 231
- 319
- 319
- 539
- 737
- 484
- 1287
- 1034
- 638
- 1122
- 759
- 781
- 550
- 957
- 627
- 572
- 957
- 605
- 671
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