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
- 1.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 2.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 3.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?
- 4.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 5.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 6.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 7.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?
- 8.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.A leapfrog list starts 1, 7 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, 7 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): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 12.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 13.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 14.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 15.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 16.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 17.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?
- 18.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 19.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 20.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 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.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?
- 23.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 24.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?
- 25.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?
- 26.A leapfrog list starts 3, 4 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): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 28.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 29.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?
- 30.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 31.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 32.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 33.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 34.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?
- 35.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?
- 36.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?
- 37.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 38.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 39.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 40.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?
Answer key
- 814
- 231
- 429
- 495
- 737
- 979
- 528
- 1023
- 671
- 1056
- 935
- 517
- 726
- 1199
- 1199
- 231
- 143
- 198
- 1232
- 660
- 869
- 968
- 583
- 495
- 1089
- 517
- 1144
- 319
- 847
- 781
- 396
- 198
- 704
- 506
- 407
- 693
- 484
- 858
- 1287
- 1023
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