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): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 2.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 3.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 4.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 5.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 6.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?
- 7.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?
- 8.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?
- 9.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 11.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?
- 12.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 14.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 15.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?
- 16.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 17.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 18.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 19.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?
- 20.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 21.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 22.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?
- 23.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 24.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 25.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 26.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 28.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 29.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 30.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 31.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?
- 32.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 33.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 34.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?
- 35.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 36.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?
- 37.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?
- 38.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 40.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
Answer key
- 748
- 1034
- 847
- 418
- 1012
- 1067
- 858
- 561
- 649
- 1144
- 495
- 1177
- 583
- 1089
- 143
- 649
- 693
- 1023
- 1056
- 1177
- 1199
- 715
- 429
- 924
- 473
- 902
- 561
- 803
- 550
- 671
- 594
- 605
- 396
- 418
- 968
- 363
- 660
- 561
- 462
- 759
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