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, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 2.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 3.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?
- 4.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.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?
- 6.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 7.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 8.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 9.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?
- 10.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?
- 11.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 12.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 13.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 15.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.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?
- 17.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 18.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 19.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?
- 20.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 21.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 22.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 24.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 26.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 28.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 29.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.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?
- 31.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 32.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 33.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 34.A leapfrog list starts 8, 1 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?
- 36.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 37.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 38.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 39.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 40.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
Answer key
- 726
- 1012
- 495
- 671
- 506
- 572
- 1111
- 1034
- 891
- 572
- 583
- 660
- 462
- 605
- 1001
- 1287
- 143
- 671
- 583
- 583
- 704
- 473
- 517
- 451
- 726
- 1067
- 803
- 561
- 1122
- 693
- 231
- 869
- 847
- 528
- 319
- 418
- 286
- 594
- 649
- 957
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