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
- 1.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 2.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?
- 3.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 4.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 6.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 8.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?
- 9.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 10.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?
- 11.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 12.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 14.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 16.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?
- 17.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 18.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 19.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 20.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 21.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 22.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?
- 23.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?
- 24.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 25.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?
- 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.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?
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 30.A leapfrog list starts 6, 7 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): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 32.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.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?
- 34.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 35.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 36.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 37.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?
- 38.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 40.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 1287
- 418
- 462
- 407
- 528
- 781
- 286
- 143
- 726
- 1089
- 418
- 363
- 517
- 143
- 198
- 737
- 308
- 374
- 759
- 814
- 869
- 671
- 462
- 748
- 748
- 506
- 836
- 583
- 253
- 946
- 506
- 759
- 143
- 605
- 1232
- 913
- 902
- 1199
- 253
- 880
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