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): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 2.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?
- 3.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 5.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?
- 6.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 7.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 8.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.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?
- 10.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.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?
- 12.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 13.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 15.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?
- 16.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 17.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?
- 18.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 20.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 21.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 23.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 24.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 25.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 26.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 27.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 28.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 29.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?
- 30.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 31.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?
- 32.A leapfrog list starts 3, 1 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): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 34.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 35.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?
- 36.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 37.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 38.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 39.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 40.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
Answer key
- 902
- 759
- 913
- 836
- 363
- 671
- 803
- 583
- 473
- 935
- 671
- 429
- 583
- 957
- 143
- 814
- 286
- 517
- 770
- 1232
- 231
- 550
- 891
- 594
- 671
- 616
- 748
- 671
- 1287
- 495
- 561
- 253
- 198
- 583
- 616
- 583
- 704
- 1144
- 1023
- 451
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