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.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 3.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 4.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?
- 5.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 6.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 7.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 8.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 9.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?
- 10.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?
- 11.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 12.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 13.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 14.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 15.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?
- 16.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?
- 17.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?
- 18.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 19.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?
- 20.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?
- 21.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 22.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 23.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.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?
- 25.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?
- 26.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?
- 27.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 29.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 31.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?
- 32.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?
- 33.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 34.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 35.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 36.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?
- 37.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 38.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 39.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
Answer key
- 869
- 407
- 506
- 319
- 1177
- 286
- 880
- 484
- 880
- 363
- 143
- 935
- 341
- 858
- 671
- 616
- 1067
- 231
- 319
- 473
- 803
- 528
- 737
- 913
- 968
- 605
- 803
- 1287
- 1034
- 1012
- 1199
- 407
- 649
- 286
- 902
- 957
- 517
- 1023
- 572
- 693
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