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
- 1.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 2.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 3.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?
- 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): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 6.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.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?
- 8.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 9.A leapfrog list starts 8, 8 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 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.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?
- 12.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 13.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?
- 14.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 15.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 17.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?
- 18.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 20.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?
- 21.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?
- 22.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?
- 23.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?
- 24.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?
- 25.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?
- 26.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?
- 27.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?
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 30.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 31.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?
- 32.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 33.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?
- 34.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 35.A leapfrog list starts 2, 1 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): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 37.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 38.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 39.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 40.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
Answer key
- 550
- 319
- 1012
- 671
- 902
- 594
- 1023
- 473
- 1144
- 473
- 968
- 506
- 583
- 286
- 748
- 759
- 561
- 1177
- 902
- 572
- 847
- 693
- 143
- 429
- 957
- 671
- 462
- 561
- 1089
- 583
- 418
- 572
- 847
- 847
- 198
- 407
- 979
- 726
- 1001
- 198
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