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): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
- 2.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 3.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?
- 4.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 5.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 6.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 7.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?
- 8.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 9.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.A leapfrog list starts 8, 9 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): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 12.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 13.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?
- 14.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 16.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 17.A leapfrog list starts 7, 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 6, 3 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 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.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?
- 21.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 22.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?
- 23.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 24.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 25.A leapfrog list starts 2, 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): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 27.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 28.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 29.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 31.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 32.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?
- 33.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 34.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?
- 35.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
- 36.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?
- 37.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?
- 38.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?
- 39.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 40.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
Answer key
- 671
- 418
- 396
- 231
- 803
- 506
- 561
- 836
- 968
- 1232
- 308
- 407
- 517
- 605
- 308
- 627
- 473
- 594
- 528
- 319
- 506
- 946
- 660
- 528
- 550
- 825
- 759
- 891
- 924
- 748
- 539
- 495
- 363
- 1012
- 1067
- 319
- 891
- 429
- 682
- 374
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