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, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 2.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?
- 3.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?
- 4.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 5.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 6.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 8.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 9.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 10.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?
- 11.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 12.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?
- 13.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 14.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?
- 15.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 16.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.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?
- 18.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 19.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 20.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 21.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?
- 22.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 23.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 25.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 26.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?
- 27.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?
- 28.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 29.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 30.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 31.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.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?
- 33.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 35.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 36.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 37.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?
- 38.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?
- 39.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 40.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
Answer key
- 1144
- 231
- 561
- 792
- 396
- 550
- 946
- 715
- 451
- 913
- 737
- 1023
- 418
- 748
- 1034
- 198
- 429
- 1111
- 924
- 418
- 1056
- 550
- 594
- 1023
- 308
- 935
- 143
- 693
- 473
- 891
- 781
- 1144
- 341
- 726
- 968
- 726
- 858
- 847
- 594
- 803
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