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.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 3.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 5.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 6.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 7.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?
- 8.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 9.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?
- 10.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 11.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 12.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?
- 13.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 14.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 15.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 16.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 17.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 18.A leapfrog list starts 6, 6 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 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.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?
- 21.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 22.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 23.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?
- 24.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 26.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 27.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?
- 28.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
- 29.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 30.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 31.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?
- 32.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?
- 33.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 34.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 35.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 36.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?
- 37.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?
- 38.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 39.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?
- 40.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
Answer key
- 374
- 869
- 759
- 770
- 1111
- 814
- 539
- 836
- 528
- 396
- 913
- 1089
- 286
- 473
- 649
- 616
- 396
- 858
- 737
- 429
- 462
- 341
- 495
- 1122
- 198
- 539
- 341
- 1177
- 748
- 671
- 869
- 770
- 429
- 231
- 946
- 902
- 726
- 561
- 561
- 1023
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