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): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 2.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 3.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 4.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 5.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?
- 6.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 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.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 9.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 11.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
- 12.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?
- 13.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
- 14.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 16.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 17.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.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?
- 20.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 21.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 22.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 23.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 24.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?
- 25.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 26.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?
- 27.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 28.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?
- 29.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 30.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 31.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 33.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 34.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?
- 35.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 37.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 38.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?
- 39.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?
- 40.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
Answer key
- 880
- 341
- 803
- 682
- 473
- 968
- 1144
- 308
- 715
- 1089
- 1067
- 649
- 429
- 935
- 517
- 418
- 627
- 484
- 253
- 517
- 1177
- 957
- 858
- 759
- 583
- 572
- 825
- 418
- 1111
- 660
- 539
- 407
- 341
- 616
- 319
- 374
- 495
- 913
- 1023
- 286
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