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.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 2.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 3.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 5.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 6.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 7.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 8.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?
- 9.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 10.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 11.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 12.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 13.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.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?
- 15.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 17.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 18.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?
- 19.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?
- 20.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 21.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 22.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?
- 23.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 24.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?
- 25.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 27.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 28.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?
- 29.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?
- 30.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?
- 31.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 32.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 33.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 34.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.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?
- 36.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 38.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?
- 39.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?
- 40.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
Answer key
- 836
- 1001
- 649
- 451
- 869
- 616
- 484
- 627
- 572
- 935
- 517
- 627
- 583
- 231
- 847
- 429
- 1023
- 968
- 506
- 715
- 693
- 418
- 1287
- 319
- 550
- 418
- 308
- 1144
- 1177
- 495
- 726
- 803
- 616
- 726
- 319
- 1177
- 671
- 704
- 429
- 143
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