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): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 2.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 3.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 4.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 5.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 6.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 7.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?
- 8.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 10.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 12.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 13.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 15.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?
- 16.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?
- 17.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 18.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?
- 19.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 20.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 21.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 22.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?
- 23.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 24.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?
- 25.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 26.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 27.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 28.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 29.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 31.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 32.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 33.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 34.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?
- 35.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 37.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?
- 38.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 39.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 40.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 726
- 759
- 506
- 572
- 363
- 946
- 1056
- 1287
- 1144
- 616
- 704
- 847
- 495
- 935
- 396
- 957
- 374
- 517
- 869
- 198
- 517
- 363
- 737
- 605
- 1111
- 396
- 1089
- 913
- 528
- 462
- 935
- 649
- 979
- 627
- 594
- 484
- 506
- 1287
- 649
- 825
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