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
- 1.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 2.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?
- 3.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 4.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 5.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 6.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?
- 7.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 8.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?
- 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.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 13.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?
- 14.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 15.A leapfrog list starts 4, 1 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 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 18.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 19.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?
- 20.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 21.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 22.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?
- 23.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?
- 24.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 25.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 26.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?
- 27.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 28.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 29.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?
- 30.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 32.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 33.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 34.A leapfrog list starts 5, 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 1, 7 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 6, 2 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, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 38.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 40.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
Answer key
- 253
- 968
- 1001
- 1001
- 858
- 935
- 770
- 814
- 286
- 825
- 891
- 616
- 319
- 198
- 308
- 781
- 286
- 616
- 781
- 704
- 143
- 957
- 1287
- 880
- 143
- 715
- 374
- 1287
- 286
- 803
- 869
- 583
- 803
- 451
- 671
- 506
- 847
- 539
- 759
- 1089
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