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
- 1.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 2.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?
- 3.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 4.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?
- 5.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?
- 6.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 7.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 9.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 11.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 12.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?
- 13.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 14.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?
- 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 16.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?
- 17.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?
- 18.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 19.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?
- 20.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 21.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?
- 22.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?
- 23.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 24.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 25.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?
- 26.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 27.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 28.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?
- 29.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?
- 30.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 31.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 32.A leapfrog list starts 8, 7 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): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 34.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?
- 35.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 37.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?
- 38.A leapfrog list starts 8, 3 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 =
- 40.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
Answer key
- 143
- 341
- 231
- 671
- 847
- 682
- 605
- 1023
- 748
- 517
- 561
- 1023
- 495
- 231
- 198
- 682
- 143
- 583
- 781
- 660
- 407
- 671
- 836
- 528
- 363
- 1056
- 858
- 506
- 1144
- 473
- 407
- 1056
- 539
- 759
- 484
- 506
- 253
- 704
- 1177
- 616
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