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 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 3.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?
- 4.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 5.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?
- 6.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 7.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?
- 8.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?
- 9.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?
- 10.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 11.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.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?
- 13.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 14.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?
- 15.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?
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 18.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 19.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?
- 20.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 21.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?
- 22.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 23.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 24.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 25.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 26.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?
- 27.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?
- 28.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?
- 29.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?
- 30.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 31.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 32.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 33.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 34.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 35.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?
- 36.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?
- 37.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 38.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?
- 39.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?
- 40.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
Answer key
- 495
- 198
- 341
- 231
- 781
- 308
- 1001
- 396
- 616
- 484
- 858
- 231
- 693
- 1177
- 737
- 627
- 550
- 880
- 616
- 737
- 847
- 880
- 638
- 671
- 539
- 572
- 1056
- 319
- 1023
- 704
- 550
- 616
- 957
- 286
- 286
- 781
- 363
- 814
- 693
- 1122
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