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): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 2.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 3.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 4.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?
- 5.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 6.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?
- 7.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 8.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?
- 9.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?
- 10.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 11.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?
- 12.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 13.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 14.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?
- 15.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.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?
- 17.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 18.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 19.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 20.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 21.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 22.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 23.A leapfrog list starts 2, 6 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 2, 9 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 8, 2 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): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 27.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?
- 28.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?
- 29.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 30.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 31.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 32.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 33.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 34.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 35.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?
- 36.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?
- 37.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 40.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?
Answer key
- 319
- 1232
- 539
- 407
- 1067
- 605
- 429
- 1089
- 902
- 1001
- 649
- 946
- 561
- 143
- 1111
- 1023
- 1144
- 814
- 803
- 759
- 957
- 506
- 638
- 902
- 616
- 198
- 759
- 891
- 891
- 902
- 781
- 550
- 924
- 825
- 572
- 561
- 660
- 726
- 583
- 473
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