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, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 2.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?
- 3.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 4.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 5.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.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?
- 8.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 12.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 13.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 14.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 15.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?
- 16.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.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?
- 19.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 20.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 21.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 22.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 23.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?
- 24.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?
- 25.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 26.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?
- 27.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 28.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 29.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?
- 30.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 31.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?
- 32.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 33.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?
- 34.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 35.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 36.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 37.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?
- 38.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 39.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
Answer key
- 880
- 451
- 627
- 198
- 715
- 253
- 814
- 451
- 484
- 473
- 671
- 418
- 231
- 957
- 319
- 979
- 935
- 968
- 803
- 803
- 957
- 616
- 396
- 616
- 286
- 1012
- 924
- 528
- 1034
- 143
- 418
- 605
- 495
- 594
- 407
- 759
- 737
- 396
- 891
- 253
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