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, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 2.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?
- 3.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 4.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?
- 5.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 6.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 7.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 8.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 9.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?
- 10.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 11.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?
- 12.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 13.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 14.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 15.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 16.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 17.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 18.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 19.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 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?
- 21.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 22.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 23.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?
- 24.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 25.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?
- 26.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 27.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 28.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.A leapfrog list starts 1, 3 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): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 32.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 33.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.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?
- 35.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?
- 36.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 37.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?
- 38.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 40.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
Answer key
- 704
- 902
- 946
- 561
- 429
- 583
- 847
- 550
- 143
- 715
- 473
- 759
- 253
- 143
- 561
- 583
- 693
- 1144
- 418
- 451
- 594
- 231
- 429
- 1199
- 770
- 407
- 517
- 374
- 308
- 319
- 825
- 495
- 231
- 1287
- 968
- 495
- 847
- 671
- 792
- 451
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