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.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?
- 2.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 3.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 4.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?
- 5.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 6.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 7.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 8.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?
- 9.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 11.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 12.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?
- 13.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?
- 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): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 16.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?
- 17.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 18.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 20.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 21.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?
- 22.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 23.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?
- 24.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
- 25.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 26.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 27.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 28.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 29.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 30.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 31.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?
- 32.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 33.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 34.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?
- 35.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 36.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.A leapfrog list starts 5, 9 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): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 39.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?
- 40.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?
Answer key
- 374
- 869
- 462
- 759
- 374
- 935
- 528
- 605
- 660
- 759
- 451
- 407
- 946
- 341
- 253
- 231
- 682
- 418
- 693
- 341
- 869
- 1012
- 737
- 638
- 902
- 968
- 704
- 781
- 814
- 836
- 462
- 550
- 198
- 1199
- 1287
- 847
- 1067
- 913
- 1144
- 1056
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