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 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 3.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 6.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?
- 7.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 8.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 11.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 12.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?
- 13.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 14.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 16.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 17.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?
- 18.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 19.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?
- 20.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 21.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.A leapfrog list starts 9, 2 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): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 24.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 25.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.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?
- 27.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 28.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 29.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 30.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?
- 31.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 32.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?
- 33.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?
- 34.A leapfrog list starts 9, 7 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 1, 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 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.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?
- 38.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 39.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
Answer key
- 407
- 836
- 572
- 1287
- 1012
- 770
- 1034
- 902
- 715
- 935
- 517
- 539
- 726
- 495
- 671
- 814
- 847
- 1056
- 660
- 847
- 231
- 671
- 1144
- 605
- 484
- 374
- 1232
- 429
- 968
- 143
- 231
- 1034
- 814
- 1111
- 847
- 473
- 1287
- 407
- 363
- 495
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