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 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 3.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 4.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 5.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 6.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 7.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?
- 8.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?
- 9.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?
- 10.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 12.A leapfrog list starts 6, 3 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 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 15.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 16.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?
- 17.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 18.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 19.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?
- 20.A leapfrog list starts 8, 2 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): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 22.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 23.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 24.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 25.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 26.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 27.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?
- 28.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 29.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 30.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 33.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?
- 34.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 35.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.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?
- 37.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?
- 38.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?
- 39.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
Answer key
- 550
- 341
- 308
- 363
- 198
- 649
- 847
- 946
- 143
- 451
- 946
- 594
- 1034
- 726
- 418
- 473
- 1034
- 704
- 693
- 616
- 583
- 836
- 671
- 1111
- 1199
- 572
- 1111
- 583
- 594
- 638
- 319
- 572
- 836
- 506
- 825
- 891
- 143
- 715
- 968
- 957
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