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 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 3.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 4.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 5.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 6.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 7.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?
- 8.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?
- 9.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?
- 10.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?
- 11.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 12.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 13.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 15.A leapfrog list starts 6, 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 7, 4 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, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 18.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?
- 19.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 20.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 21.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?
- 22.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?
- 23.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 24.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 25.A leapfrog list starts 9, 3 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, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 27.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 28.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 29.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?
- 30.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?
- 31.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 32.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 33.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 34.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 36.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.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?
- 38.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 39.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?
- 40.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
Answer key
- 308
- 374
- 561
- 781
- 396
- 253
- 924
- 286
- 1023
- 418
- 550
- 539
- 1144
- 682
- 594
- 737
- 1023
- 869
- 528
- 814
- 737
- 473
- 583
- 484
- 759
- 341
- 198
- 1199
- 231
- 605
- 957
- 517
- 429
- 1232
- 858
- 660
- 935
- 836
- 979
- 847
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