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 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 2.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?
- 3.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?
- 4.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?
- 5.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 6.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 7.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?
- 8.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?
- 9.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 10.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?
- 11.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 12.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 13.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?
- 14.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?
- 15.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?
- 16.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?
- 17.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.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?
- 20.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?
- 21.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 22.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 23.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 25.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 27.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 28.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 29.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 30.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.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?
- 32.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 33.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?
- 34.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 35.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 38.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 39.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?
- 40.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
Answer key
- 924
- 451
- 1067
- 935
- 451
- 495
- 429
- 495
- 286
- 825
- 748
- 363
- 1287
- 341
- 396
- 627
- 1012
- 825
- 605
- 869
- 1023
- 858
- 671
- 913
- 594
- 143
- 572
- 1287
- 605
- 286
- 429
- 231
- 341
- 583
- 704
- 968
- 759
- 407
- 671
- 1232
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