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): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 2.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 3.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 5.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?
- 6.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 7.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 9.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 10.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 11.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 12.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 13.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.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?
- 15.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 16.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 17.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?
- 18.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 19.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?
- 20.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 21.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?
- 22.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 23.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 25.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?
- 26.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?
- 27.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?
- 28.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.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?
- 30.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?
- 31.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 34.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?
- 35.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 36.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 37.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?
- 38.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?
- 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 40.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?
Answer key
- 418
- 363
- 715
- 1067
- 473
- 891
- 451
- 583
- 319
- 671
- 671
- 341
- 1089
- 198
- 814
- 660
- 759
- 1199
- 803
- 935
- 968
- 198
- 374
- 407
- 682
- 594
- 880
- 1144
- 627
- 506
- 198
- 550
- 539
- 341
- 869
- 880
- 429
- 1287
- 616
- 583
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