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): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 2.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 3.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 4.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?
- 5.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?
- 6.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 7.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?
- 8.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?
- 9.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
- 10.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 11.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 12.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?
- 13.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?
- 14.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 15.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 16.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 17.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
- 18.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 19.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 20.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 21.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 22.A leapfrog list starts 6, 5 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): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 24.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 25.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.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?
- 27.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?
- 28.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 29.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?
- 30.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 31.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?
- 32.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 33.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?
- 34.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?
- 35.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?
- 36.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 37.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 38.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?
- 39.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 40.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
Answer key
- 968
- 418
- 1067
- 341
- 473
- 429
- 495
- 1287
- 946
- 748
- 583
- 957
- 605
- 704
- 770
- 1177
- 638
- 286
- 286
- 781
- 891
- 770
- 847
- 1144
- 429
- 1122
- 935
- 946
- 616
- 1056
- 528
- 759
- 561
- 583
- 396
- 803
- 660
- 737
- 693
- 682
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