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 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 2.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 3.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 4.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 5.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 6.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 7.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?
- 8.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 9.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?
- 10.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 11.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 12.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 13.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?
- 14.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 15.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 16.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 17.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 18.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?
- 19.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 20.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 21.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?
- 22.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?
- 23.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 24.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 25.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?
- 26.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?
- 27.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 28.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?
- 29.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 30.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 31.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 32.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 33.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 34.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 35.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 36.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 38.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 39.A leapfrog list starts 5, 3 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): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
Answer key
- 495
- 759
- 715
- 539
- 484
- 1287
- 363
- 968
- 484
- 374
- 792
- 935
- 396
- 627
- 341
- 429
- 572
- 836
- 847
- 979
- 1089
- 561
- 319
- 902
- 803
- 759
- 473
- 396
- 1122
- 1232
- 847
- 286
- 770
- 550
- 605
- 1001
- 825
- 1287
- 539
- 429
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