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): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. 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, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 5.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 6.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 7.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?
- 8.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 9.A leapfrog list starts 8, 2 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): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 11.A leapfrog list starts 4, 5 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): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 13.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 15.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?
- 16.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 17.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 18.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.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?
- 20.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 22.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 23.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 26.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 27.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?
- 28.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?
- 29.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 30.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?
- 31.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 32.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?
- 33.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?
- 34.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?
- 35.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 36.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?
- 37.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 38.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 39.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 40.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
Answer key
- 671
- 1012
- 671
- 341
- 737
- 517
- 198
- 847
- 616
- 231
- 660
- 198
- 649
- 1122
- 693
- 913
- 1012
- 726
- 671
- 627
- 869
- 484
- 902
- 759
- 759
- 671
- 605
- 1034
- 968
- 979
- 583
- 572
- 418
- 583
- 572
- 539
- 143
- 341
- 1067
- 924
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