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, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 3.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 4.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 5.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?
- 6.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 7.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 9.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?
- 10.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 11.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 12.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 13.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?
- 14.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.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?
- 16.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?
- 17.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?
- 18.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?
- 19.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?
- 20.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?
- 21.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?
- 22.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 23.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?
- 24.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?
- 25.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?
- 26.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?
- 27.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 29.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?
- 30.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?
- 31.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?
- 32.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 33.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 34.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?
- 35.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 36.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 37.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?
- 38.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 39.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
Answer key
- 605
- 770
- 847
- 704
- 616
- 143
- 814
- 473
- 495
- 726
- 792
- 286
- 198
- 429
- 913
- 462
- 693
- 924
- 572
- 495
- 319
- 396
- 660
- 825
- 517
- 506
- 627
- 649
- 671
- 968
- 341
- 583
- 682
- 1122
- 737
- 726
- 781
- 979
- 891
- 198
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