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
- 1.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 2.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 3.A leapfrog list starts 6, 1 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): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 5.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 6.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 7.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 8.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 9.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?
- 10.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 11.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 12.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 13.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?
- 14.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 15.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 16.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.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?
- 18.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 19.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 20.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.A leapfrog list starts 3, 4 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): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 24.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 25.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 26.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
- 27.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 28.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 29.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?
- 30.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.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?
- 34.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?
- 35.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 37.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 38.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 39.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 40.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
Answer key
- 539
- 726
- 418
- 781
- 506
- 891
- 1056
- 660
- 858
- 429
- 880
- 484
- 847
- 979
- 528
- 1144
- 539
- 693
- 583
- 616
- 583
- 517
- 374
- 572
- 473
- 1067
- 319
- 671
- 550
- 880
- 759
- 836
- 231
- 1144
- 594
- 1012
- 935
- 517
- 473
- 913
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