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.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?
- 2.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 3.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?
- 4.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?
- 5.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?
- 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.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?
- 8.A leapfrog list starts 3, 7 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, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 10.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 11.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?
- 12.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 14.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 15.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 16.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 17.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 18.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
- 19.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?
- 20.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?
- 21.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?
- 22.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 23.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 24.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 25.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?
- 26.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 27.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?
- 28.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?
- 29.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 30.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 31.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 33.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.A leapfrog list starts 3, 9 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 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 37.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?
- 38.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 39.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 40.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
Answer key
- 517
- 1001
- 1001
- 396
- 759
- 308
- 506
- 781
- 869
- 748
- 1199
- 473
- 825
- 847
- 550
- 253
- 308
- 671
- 605
- 1122
- 671
- 968
- 660
- 704
- 143
- 627
- 1177
- 891
- 814
- 363
- 946
- 902
- 803
- 957
- 253
- 1056
- 704
- 759
- 231
- 726
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