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
- 1.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 2.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 3.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 4.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 5.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 6.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.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?
- 8.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 10.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 12.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 13.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 15.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?
- 16.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?
- 17.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?
- 18.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.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?
- 20.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?
- 21.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 22.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 23.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?
- 24.A leapfrog list starts 6, 2 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 26.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?
- 27.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 29.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 30.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 31.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?
- 32.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 33.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 34.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?
- 35.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 36.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 37.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 38.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?
- 39.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 40.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 902
- 396
- 517
- 462
- 836
- 1177
- 638
- 1199
- 693
- 319
- 671
- 671
- 671
- 1144
- 979
- 638
- 363
- 286
- 649
- 682
- 605
- 891
- 1023
- 506
- 1056
- 979
- 143
- 1089
- 968
- 550
- 814
- 1111
- 198
- 341
- 660
- 858
- 891
- 198
- 759
- 363
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