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 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 2.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 3.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 4.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 5.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 6.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 7.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 10.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 11.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 12.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 13.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?
- 14.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 16.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 17.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?
- 18.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?
- 19.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 20.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 21.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?
- 22.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 23.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 24.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 26.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?
- 27.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?
- 28.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 29.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?
- 30.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?
- 31.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 32.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 33.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?
- 34.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 35.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 36.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?
- 37.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?
- 38.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 39.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 40.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
Answer key
- 1067
- 627
- 979
- 1023
- 363
- 968
- 737
- 913
- 396
- 341
- 286
- 1122
- 143
- 693
- 1056
- 737
- 1287
- 880
- 583
- 484
- 572
- 363
- 616
- 407
- 1089
- 1089
- 1034
- 726
- 836
- 880
- 1287
- 671
- 638
- 1144
- 814
- 484
- 858
- 770
- 374
- 693
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