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 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 2.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 3.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 4.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?
- 5.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?
- 6.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 7.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?
- 8.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?
- 9.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 10.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 11.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 12.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 13.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 14.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 15.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 17.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?
- 18.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 19.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 20.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 21.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 22.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?
- 23.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 24.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.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?
- 27.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?
- 28.A leapfrog list starts 2, 8 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 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 31.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 32.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?
- 33.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 34.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 35.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?
- 36.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 37.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 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.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
- 40.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?
Answer key
- 1056
- 924
- 902
- 583
- 1089
- 847
- 737
- 781
- 319
- 572
- 539
- 1023
- 253
- 528
- 869
- 957
- 231
- 1012
- 231
- 583
- 781
- 363
- 1034
- 1023
- 627
- 418
- 858
- 814
- 913
- 748
- 825
- 649
- 605
- 495
- 286
- 1056
- 913
- 638
- 1232
- 814
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