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): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 2.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 3.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 4.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 5.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?
- 6.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 7.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 9.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?
- 10.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 11.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 12.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 13.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 14.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 15.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 16.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 17.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?
- 18.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?
- 19.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 20.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 21.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 23.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 24.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 25.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?
- 26.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 27.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?
- 28.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?
- 29.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 30.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?
- 31.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 32.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 33.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 34.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 35.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?
- 36.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.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?
- 39.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 40.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
Answer key
- 957
- 979
- 253
- 924
- 462
- 286
- 858
- 759
- 869
- 550
- 836
- 583
- 484
- 583
- 1144
- 968
- 913
- 539
- 319
- 198
- 825
- 462
- 539
- 627
- 517
- 506
- 231
- 616
- 814
- 561
- 660
- 374
- 616
- 583
- 407
- 1199
- 539
- 528
- 231
- 924
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