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, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 2.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?
- 3.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 4.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 5.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?
- 6.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 8.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?
- 9.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?
- 10.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 11.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 12.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 13.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?
- 14.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?
- 15.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 16.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 17.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 19.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 20.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 21.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 23.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.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?
- 25.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?
- 26.A leapfrog list starts 8, 1 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): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 28.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 29.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?
- 30.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?
- 31.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 32.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 33.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 34.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 36.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 37.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 39.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?
- 40.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
Answer key
- 341
- 1232
- 429
- 374
- 649
- 770
- 143
- 1056
- 1067
- 671
- 286
- 539
- 407
- 913
- 495
- 847
- 1001
- 759
- 924
- 869
- 396
- 462
- 671
- 583
- 902
- 528
- 671
- 902
- 198
- 143
- 682
- 407
- 1199
- 671
- 594
- 308
- 583
- 253
- 484
- 198
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