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 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 2.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 3.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 4.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?
- 5.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 6.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?
- 7.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 8.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 9.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?
- 10.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 11.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
- 12.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 13.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 14.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?
- 15.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?
- 16.A leapfrog list starts 5, 4 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 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 19.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 20.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?
- 21.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?
- 22.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 23.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 24.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 25.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 26.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?
- 27.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 28.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?
- 29.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?
- 30.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 31.A leapfrog list starts 2, 1 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?
- 33.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 34.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 36.A leapfrog list starts 9, 5 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 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.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?
Answer key
- 319
- 803
- 363
- 1199
- 572
- 308
- 253
- 143
- 517
- 814
- 946
- 825
- 484
- 198
- 418
- 627
- 561
- 1056
- 1199
- 1067
- 858
- 583
- 517
- 396
- 550
- 913
- 979
- 1001
- 1089
- 473
- 198
- 836
- 418
- 550
- 715
- 935
- 1111
- 396
- 891
- 759
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