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): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 2.A leapfrog list starts 9, 8 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 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 5.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 6.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 7.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 8.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?
- 9.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 10.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 11.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 12.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?
- 13.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?
- 14.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 15.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 16.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 17.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?
- 18.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?
- 19.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 20.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 22.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?
- 23.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?
- 24.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 25.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 26.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 28.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?
- 29.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 30.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 31.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?
- 32.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?
- 33.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 34.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 35.A leapfrog list starts 3, 9 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): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 37.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?
- 38.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?
- 39.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?
- 40.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
Answer key
- 693
- 1199
- 308
- 517
- 506
- 770
- 495
- 583
- 528
- 462
- 891
- 473
- 1111
- 913
- 462
- 1199
- 638
- 319
- 737
- 968
- 847
- 253
- 539
- 1067
- 726
- 847
- 781
- 484
- 715
- 616
- 407
- 924
- 1111
- 561
- 957
- 957
- 891
- 1232
- 1056
- 968
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