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
- 1.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 2.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 3.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.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?
- 5.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 6.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?
- 7.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?
- 8.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?
- 9.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 10.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 11.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 12.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?
- 13.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?
- 14.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 15.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.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?
- 17.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 18.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 19.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 21.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 22.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?
- 23.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?
- 24.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 25.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?
- 26.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 27.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 28.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 29.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 30.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 31.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 32.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?
- 33.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 34.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?
- 35.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?
- 36.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 37.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?
- 38.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?
- 39.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 506
- 1177
- 1012
- 583
- 847
- 891
- 429
- 539
- 517
- 1199
- 627
- 1001
- 979
- 1111
- 1232
- 341
- 1034
- 759
- 693
- 847
- 1001
- 847
- 319
- 253
- 693
- 319
- 638
- 583
- 968
- 583
- 759
- 198
- 407
- 143
- 682
- 792
- 528
- 1056
- 759
- 836
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