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): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 2.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 3.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 4.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?
- 5.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 6.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 7.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 8.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 9.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 11.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 12.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?
- 13.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 14.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 15.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.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?
- 17.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 18.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 19.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?
- 20.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.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?
- 23.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?
- 24.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 25.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 26.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 27.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?
- 28.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?
- 29.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 31.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 32.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 33.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 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 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 37.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?
- 38.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 39.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 40.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
Answer key
- 407
- 1001
- 473
- 770
- 979
- 726
- 231
- 594
- 869
- 858
- 792
- 253
- 286
- 1012
- 1056
- 374
- 704
- 451
- 429
- 847
- 451
- 1067
- 814
- 550
- 759
- 583
- 583
- 374
- 979
- 451
- 715
- 1287
- 1023
- 616
- 1144
- 880
- 671
- 1067
- 660
- 539
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