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): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 2.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?
- 3.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 5.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 6.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 7.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 8.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 9.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 10.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 12.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 13.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 14.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 15.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 16.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 17.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?
- 18.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 19.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 20.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 21.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 22.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 23.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 25.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?
- 26.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 27.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?
- 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?
- 29.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 30.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?
- 31.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?
- 32.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 33.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 34.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 35.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 36.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 37.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 39.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?
- 40.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?
Answer key
- 517
- 638
- 759
- 429
- 847
- 737
- 286
- 759
- 627
- 880
- 605
- 583
- 638
- 1012
- 781
- 561
- 143
- 957
- 759
- 451
- 605
- 1001
- 715
- 539
- 561
- 308
- 253
- 1001
- 253
- 957
- 847
- 715
- 198
- 1034
- 1177
- 726
- 726
- 484
- 198
- 484
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