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
- 1.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 2.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 3.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 4.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
- 5.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 6.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 7.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 8.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 10.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 11.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?
- 12.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?
- 13.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 14.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?
- 15.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?
- 16.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?
- 17.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?
- 18.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 19.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 20.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 22.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 23.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?
- 24.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 25.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 27.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?
- 28.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 29.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 30.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 31.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 32.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?
- 33.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 34.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?
- 35.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 36.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 37.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 38.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 39.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 40.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
Answer key
- 429
- 308
- 979
- 1177
- 1012
- 704
- 539
- 825
- 1001
- 495
- 814
- 737
- 341
- 737
- 253
- 924
- 759
- 1144
- 913
- 1001
- 1067
- 682
- 143
- 737
- 286
- 924
- 759
- 473
- 1023
- 517
- 825
- 462
- 1122
- 407
- 231
- 363
- 847
- 583
- 583
- 594
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