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
- 1.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 2.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 3.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 4.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?
- 5.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 6.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?
- 7.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.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?
- 9.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 10.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?
- 11.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?
- 12.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?
- 13.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?
- 14.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 15.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 17.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 18.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 19.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 20.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 21.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 22.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 23.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
- 24.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 25.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 26.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 27.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?
- 28.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 29.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?
- 30.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 31.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 32.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 33.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
- 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?
- 35.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 36.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?
- 37.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?
- 38.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.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?
- 40.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
Answer key
- 847
- 473
- 957
- 319
- 1034
- 1111
- 286
- 682
- 396
- 847
- 671
- 506
- 759
- 902
- 660
- 506
- 671
- 308
- 1111
- 528
- 198
- 594
- 1232
- 748
- 924
- 1089
- 1232
- 814
- 429
- 979
- 759
- 715
- 946
- 814
- 1177
- 517
- 198
- 550
- 198
- 759
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