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 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 2.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?
- 3.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 4.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 5.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?
- 6.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 7.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 8.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 9.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?
- 10.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 11.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 12.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?
- 13.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.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?
- 16.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 17.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?
- 18.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 19.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 20.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.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?
- 22.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?
- 23.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 24.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 25.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?
- 26.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 27.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?
- 28.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 29.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
- 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?
- 31.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 32.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?
- 33.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 34.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 36.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 37.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 38.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?
- 39.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?
- 40.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
Answer key
- 396
- 594
- 924
- 506
- 253
- 616
- 319
- 1067
- 495
- 198
- 583
- 858
- 583
- 814
- 1199
- 1287
- 1111
- 198
- 913
- 396
- 1056
- 627
- 803
- 462
- 869
- 341
- 473
- 968
- 1177
- 561
- 726
- 946
- 825
- 671
- 1023
- 396
- 572
- 484
- 1067
- 1144
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