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, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
- 2.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 3.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 4.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 5.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?
- 6.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 7.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?
- 8.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 9.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 10.A leapfrog list starts 2, 6 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 1, 8 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): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 13.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?
- 14.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?
- 15.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?
- 16.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 17.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 18.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 20.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?
- 21.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 22.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 23.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?
- 24.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 25.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 26.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 27.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 29.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 31.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 32.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 33.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?
- 34.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?
- 35.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 36.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 37.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?
- 38.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 39.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 40.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?
Answer key
- 429
- 1177
- 869
- 836
- 748
- 847
- 539
- 913
- 792
- 638
- 759
- 231
- 341
- 825
- 759
- 671
- 495
- 946
- 396
- 616
- 803
- 891
- 473
- 506
- 341
- 1232
- 759
- 407
- 869
- 649
- 517
- 968
- 286
- 869
- 143
- 891
- 341
- 605
- 253
- 1034
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