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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 2.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 3.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?
- 4.A leapfrog list starts 3, 5 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 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.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?
- 7.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 8.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 9.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 10.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?
- 11.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?
- 12.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 14.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 15.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
- 16.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 18.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 20.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?
- 21.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 22.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?
- 23.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 24.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 26.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?
- 27.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 29.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?
- 30.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 32.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?
- 33.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?
- 34.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 35.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?
- 36.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?
- 37.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?
- 38.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?
- 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 40.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
Answer key
- 143
- 561
- 847
- 605
- 814
- 759
- 913
- 550
- 913
- 143
- 1023
- 847
- 880
- 748
- 638
- 913
- 726
- 396
- 605
- 550
- 231
- 616
- 968
- 957
- 715
- 847
- 583
- 1144
- 1034
- 429
- 946
- 418
- 1034
- 924
- 495
- 693
- 1067
- 968
- 616
- 1023
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