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, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 2.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?
- 3.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 4.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 6.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 7.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.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?
- 10.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 11.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 12.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 13.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 14.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 15.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?
- 16.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 17.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 18.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 19.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 20.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 21.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 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?
- 23.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 24.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. 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.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 27.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?
- 28.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?
- 29.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 30.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 31.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 32.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 33.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 34.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 35.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?
- 36.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?
- 37.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?
- 38.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 40.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
Answer key
- 1111
- 539
- 374
- 341
- 814
- 792
- 407
- 253
- 957
- 880
- 726
- 418
- 682
- 143
- 605
- 759
- 528
- 286
- 451
- 748
- 671
- 616
- 627
- 308
- 517
- 1056
- 319
- 627
- 924
- 341
- 946
- 825
- 506
- 737
- 660
- 979
- 847
- 1111
- 913
- 539
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