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 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 3.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?
- 4.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 5.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 6.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?
- 7.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 8.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 10.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?
- 11.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 12.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 13.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?
- 14.A leapfrog list starts 2, 4 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): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 16.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 17.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?
- 18.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?
- 19.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?
- 20.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 22.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?
- 23.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 24.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 25.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?
- 26.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 27.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?
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 30.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 31.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 32.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 34.A leapfrog list starts 8, 3 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 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 38.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 40.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
Answer key
- 583
- 715
- 726
- 902
- 495
- 1001
- 616
- 1023
- 704
- 770
- 341
- 1012
- 880
- 462
- 902
- 1122
- 319
- 957
- 891
- 946
- 924
- 561
- 1287
- 1111
- 869
- 374
- 143
- 539
- 231
- 660
- 693
- 1177
- 979
- 704
- 1067
- 748
- 759
- 682
- 627
- 583
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