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): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 2.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 3.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 4.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 5.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 6.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 7.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 8.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 9.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 10.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.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?
- 12.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.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?
- 14.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?
- 15.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?
- 16.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 17.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.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?
- 19.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 21.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 22.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 23.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 24.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 25.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 26.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?
- 27.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
- 30.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 31.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?
- 32.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 33.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 34.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 36.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 37.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 38.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 39.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?
- 40.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?
Answer key
- 1034
- 902
- 583
- 891
- 957
- 363
- 517
- 473
- 594
- 814
- 858
- 748
- 143
- 583
- 847
- 462
- 198
- 957
- 462
- 759
- 1067
- 198
- 902
- 880
- 1056
- 506
- 319
- 484
- 1012
- 1232
- 605
- 781
- 825
- 693
- 605
- 704
- 616
- 429
- 517
- 1089
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