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.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?
- 2.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?
- 3.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 4.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?
- 5.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 6.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?
- 7.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 8.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?
- 9.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 10.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 11.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 12.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?
- 13.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 14.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 15.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 16.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 17.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 18.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 19.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 20.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?
- 21.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 22.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 23.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 24.A leapfrog list starts 5, 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): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 26.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 27.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 28.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?
- 29.A leapfrog list starts 5, 9 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): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 31.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?
- 32.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 33.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 34.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 35.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?
- 36.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 39.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 40.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
Answer key
- 539
- 517
- 825
- 682
- 935
- 341
- 759
- 418
- 198
- 682
- 517
- 407
- 561
- 913
- 1056
- 737
- 594
- 759
- 1199
- 671
- 1001
- 1023
- 308
- 451
- 1089
- 341
- 539
- 704
- 1067
- 1122
- 638
- 1111
- 1144
- 726
- 363
- 374
- 253
- 770
- 407
- 583
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