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): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 2.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?
- 3.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 4.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.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?
- 6.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 7.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 9.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 10.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?
- 11.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?
- 12.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?
- 13.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 14.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?
- 15.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 18.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 20.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 21.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 22.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 23.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?
- 24.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 25.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 26.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 27.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 28.A leapfrog list starts 8, 7 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 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 31.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 32.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 33.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 34.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 35.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?
- 36.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?
- 37.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 38.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 39.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 40.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
Answer key
- 935
- 913
- 583
- 704
- 528
- 528
- 1144
- 671
- 814
- 814
- 418
- 572
- 1023
- 1023
- 484
- 539
- 979
- 473
- 396
- 143
- 407
- 517
- 1001
- 198
- 781
- 286
- 583
- 1056
- 506
- 407
- 231
- 451
- 484
- 1056
- 825
- 792
- 649
- 1089
- 1232
- 1067
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