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
- 1.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 2.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 3.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 4.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 5.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 6.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 8.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 9.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.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?
- 11.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.A leapfrog list starts 4, 2 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 4, 4 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): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 15.A leapfrog list starts 6, 2 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): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 17.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?
- 18.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 19.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 20.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?
- 21.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?
- 22.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 23.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 24.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.A leapfrog list starts 5, 4 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 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 28.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 29.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 30.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 31.A leapfrog list starts 3, 1 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 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.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?
- 34.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 35.A leapfrog list starts 3, 4 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 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 38.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 39.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 40.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?
Answer key
- 781
- 671
- 715
- 660
- 880
- 308
- 253
- 847
- 792
- 429
- 924
- 396
- 572
- 341
- 506
- 308
- 1056
- 638
- 935
- 682
- 726
- 231
- 198
- 649
- 627
- 891
- 825
- 1089
- 308
- 1199
- 253
- 231
- 1001
- 473
- 517
- 341
- 836
- 429
- 1056
- 693
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