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
- 1.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 2.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 3.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 4.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 5.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.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?
- 8.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 9.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?
- 10.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 11.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?
- 12.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?
- 13.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 14.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 15.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?
- 16.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 17.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 18.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 19.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?
- 20.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 21.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 22.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?
- 23.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 24.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?
- 25.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?
- 26.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 30.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 31.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 32.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 33.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 34.A leapfrog list starts 2, 8 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, 1 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?
- 37.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 38.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 39.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?
- 40.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
Answer key
- 1144
- 143
- 1023
- 803
- 946
- 605
- 836
- 1034
- 671
- 484
- 484
- 847
- 1122
- 418
- 517
- 473
- 737
- 836
- 759
- 616
- 583
- 418
- 1111
- 231
- 198
- 704
- 319
- 308
- 484
- 198
- 682
- 462
- 407
- 814
- 528
- 473
- 935
- 660
- 1199
- 143
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