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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 2.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 3.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.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?
- 6.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 7.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?
- 8.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 9.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 10.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 11.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?
- 12.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 13.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 14.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 15.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 16.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 17.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?
- 18.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 19.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 20.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 21.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 22.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 23.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.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?
- 25.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 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?
- 27.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 30.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 31.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 32.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 33.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 34.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?
- 35.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?
- 36.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?
- 37.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
- 38.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?
- 39.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 40.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 550
- 693
- 638
- 1199
- 1023
- 759
- 968
- 803
- 726
- 583
- 583
- 143
- 1177
- 231
- 924
- 1034
- 847
- 396
- 627
- 759
- 1012
- 1144
- 363
- 814
- 1287
- 572
- 418
- 539
- 891
- 253
- 847
- 869
- 495
- 957
- 1001
- 858
- 1012
- 1023
- 143
- 1034
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