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.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.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?
- 3.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 4.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 5.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 6.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 8.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 10.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 11.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?
- 12.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 14.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 16.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 17.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 18.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 19.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.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?
- 21.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?
- 22.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 23.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 24.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.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?
- 26.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?
- 27.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 28.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 29.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 30.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?
- 31.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 32.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 33.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?
- 34.A leapfrog list starts 1, 4 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, 1 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 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 38.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 39.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 40.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
Answer key
- 418
- 143
- 583
- 836
- 451
- 572
- 374
- 550
- 1177
- 1056
- 814
- 792
- 473
- 605
- 781
- 1023
- 517
- 660
- 924
- 902
- 847
- 671
- 594
- 1012
- 935
- 363
- 803
- 583
- 1067
- 1023
- 913
- 682
- 528
- 407
- 143
- 341
- 528
- 539
- 319
- 726
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