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 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 3.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?
- 4.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 5.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?
- 6.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 7.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 8.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?
- 9.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?
- 10.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 11.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 12.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 13.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?
- 14.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 16.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?
- 17.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.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?
- 19.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?
- 20.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 21.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.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?
- 23.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 24.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 25.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?
- 26.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?
- 27.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?
- 28.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.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?
- 30.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 31.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?
- 32.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 33.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 34.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?
- 35.A leapfrog list starts 3, 7 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): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 37.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 38.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 39.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 40.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
Answer key
- 957
- 814
- 319
- 451
- 1034
- 1012
- 693
- 528
- 1056
- 957
- 1199
- 836
- 418
- 1067
- 979
- 759
- 1012
- 506
- 231
- 880
- 583
- 671
- 528
- 1287
- 517
- 616
- 473
- 759
- 649
- 231
- 594
- 759
- 605
- 957
- 781
- 726
- 1067
- 968
- 759
- 550
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