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
- 1.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 2.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 3.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 4.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 5.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 6.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 7.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?
- 8.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 9.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?
- 10.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 11.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 12.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 13.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 14.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 15.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
- 16.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 17.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?
- 18.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?
- 19.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?
- 20.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 21.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.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?
- 23.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?
- 24.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 26.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?
- 27.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 28.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 29.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?
- 30.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.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?
- 32.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 33.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?
- 34.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 36.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 37.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 38.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?
- 39.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?
- 40.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?
Answer key
- 1122
- 1287
- 792
- 957
- 858
- 1089
- 759
- 737
- 583
- 748
- 814
- 1023
- 1001
- 946
- 671
- 759
- 462
- 847
- 1122
- 462
- 1232
- 473
- 143
- 1287
- 968
- 660
- 363
- 341
- 825
- 594
- 396
- 506
- 319
- 484
- 319
- 429
- 825
- 638
- 737
- 528
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