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, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 2.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?
- 3.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 4.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 5.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?
- 6.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 7.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 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?
- 9.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 10.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 11.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 12.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 13.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 14.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 15.A leapfrog list starts 7, 3 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): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 17.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 18.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 19.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?
- 20.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 21.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?
- 22.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 23.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 24.A leapfrog list starts 3, 4 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 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 27.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 28.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?
- 29.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 31.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 32.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 33.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?
- 34.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 35.A leapfrog list starts 9, 4 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): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 37.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?
- 38.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
Answer key
- 1287
- 616
- 583
- 693
- 660
- 715
- 616
- 583
- 341
- 902
- 473
- 572
- 715
- 913
- 649
- 957
- 407
- 1001
- 649
- 671
- 957
- 891
- 143
- 517
- 836
- 660
- 869
- 1089
- 1089
- 737
- 495
- 495
- 462
- 517
- 847
- 759
- 561
- 1067
- 495
- 594
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