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): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 2.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 3.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 4.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?
- 5.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?
- 6.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 7.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 8.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?
- 9.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?
- 10.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 11.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 12.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 13.A leapfrog list starts 9, 1 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): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 15.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 16.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 17.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 18.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?
- 19.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?
- 20.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?
- 21.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 22.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?
- 23.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 24.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 26.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?
- 27.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 28.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 29.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 30.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 31.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 32.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 33.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 34.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?
- 35.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 37.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?
- 38.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 39.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 40.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
Answer key
- 1001
- 429
- 462
- 880
- 660
- 550
- 979
- 605
- 671
- 803
- 231
- 935
- 583
- 858
- 968
- 737
- 198
- 946
- 363
- 253
- 704
- 803
- 572
- 847
- 374
- 1177
- 825
- 396
- 814
- 671
- 484
- 495
- 539
- 1111
- 902
- 825
- 803
- 583
- 759
- 561
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