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 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 3.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 4.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 5.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 6.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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.A leapfrog list starts 5, 5 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 6, 5 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): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 11.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 12.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 13.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 14.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 15.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 16.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 18.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 19.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 20.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?
- 21.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 23.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 24.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 25.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 26.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?
- 27.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?
- 28.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 30.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 31.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 33.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 35.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 36.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.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?
- 38.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?
- 39.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?
- 40.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?
Answer key
- 1287
- 396
- 979
- 451
- 561
- 253
- 1001
- 715
- 770
- 462
- 1122
- 308
- 792
- 935
- 341
- 418
- 1089
- 814
- 737
- 583
- 1111
- 847
- 649
- 682
- 528
- 781
- 506
- 374
- 506
- 968
- 880
- 803
- 143
- 792
- 462
- 561
- 572
- 429
- 1287
- 396
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