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
- 1.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 2.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 3.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 5.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 7.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 8.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?
- 9.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 10.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 11.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
- 12.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 13.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 14.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 18.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 19.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?
- 20.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 21.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 22.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 23.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?
- 24.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 25.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?
- 26.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 27.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.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?
- 29.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 31.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 32.A leapfrog list starts 7, 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): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 34.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?
- 35.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?
- 36.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 37.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 38.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 40.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?
Answer key
- 1144
- 308
- 726
- 726
- 396
- 957
- 649
- 473
- 1012
- 308
- 1012
- 913
- 979
- 957
- 1122
- 858
- 737
- 869
- 1287
- 1199
- 924
- 462
- 583
- 484
- 341
- 451
- 616
- 649
- 781
- 539
- 759
- 737
- 759
- 561
- 462
- 957
- 649
- 319
- 319
- 374
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