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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 2.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 3.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 4.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 5.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 6.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 7.A leapfrog list starts 6, 5 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 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.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?
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 12.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?
- 13.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 14.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?
- 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?
- 16.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 17.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 19.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 20.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?
- 21.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 22.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 23.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 24.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?
- 25.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 26.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 27.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 29.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?
- 30.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 31.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 33.A leapfrog list starts 1, 2 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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 35.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 37.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?
- 38.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 39.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 40.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
Answer key
- 143
- 935
- 462
- 1199
- 847
- 198
- 770
- 627
- 660
- 528
- 473
- 616
- 1056
- 418
- 1144
- 561
- 913
- 913
- 726
- 869
- 781
- 649
- 671
- 473
- 1067
- 495
- 1067
- 605
- 517
- 957
- 583
- 759
- 231
- 594
- 836
- 737
- 506
- 1012
- 770
- 704
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