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
- 1.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 2.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?
- 3.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?
- 4.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 5.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 6.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?
- 7.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 9.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
- 10.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 11.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?
- 12.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 14.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 15.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?
- 16.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 17.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 18.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?
- 19.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 20.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 21.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 23.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 24.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 25.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?
- 26.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?
- 27.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 28.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 29.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?
- 30.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?
- 31.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?
- 32.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 33.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 34.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 35.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 37.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 38.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.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?
- 40.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
Answer key
- 572
- 1199
- 1144
- 583
- 341
- 759
- 319
- 1067
- 1067
- 627
- 638
- 429
- 825
- 803
- 869
- 473
- 143
- 605
- 924
- 253
- 506
- 935
- 396
- 451
- 913
- 407
- 671
- 286
- 616
- 627
- 583
- 737
- 363
- 880
- 1232
- 495
- 913
- 561
- 286
- 594
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