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
- 1.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 2.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 3.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 4.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 5.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?
- 6.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 8.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 9.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?
- 10.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 11.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 12.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?
- 13.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?
- 14.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?
- 15.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 18.A leapfrog list starts 1, 1 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): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 20.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 21.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 23.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 24.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 26.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 27.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 28.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 30.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?
- 31.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 32.A leapfrog list starts 8, 4 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): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 34.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?
- 35.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 37.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 38.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?
- 39.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
Answer key
- 550
- 979
- 781
- 836
- 1067
- 605
- 451
- 396
- 825
- 231
- 484
- 418
- 341
- 594
- 1012
- 451
- 737
- 143
- 627
- 715
- 1111
- 858
- 704
- 693
- 792
- 341
- 374
- 462
- 671
- 1089
- 1067
- 792
- 319
- 253
- 1056
- 759
- 1199
- 1012
- 363
- 660
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