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, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 3.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 4.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?
- 5.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 6.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?
- 7.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 8.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 9.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 10.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?
- 11.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?
- 12.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?
- 13.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 14.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?
- 15.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?
- 16.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 17.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?
- 18.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 19.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 20.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 21.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 22.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 23.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 24.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?
- 25.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 26.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 27.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 28.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 29.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 30.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 31.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 32.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.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?
- 34.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 35.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 37.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 38.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 39.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?
- 40.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?
Answer key
- 605
- 682
- 451
- 781
- 539
- 1034
- 319
- 286
- 495
- 627
- 693
- 583
- 902
- 517
- 594
- 1067
- 792
- 957
- 913
- 528
- 198
- 858
- 594
- 814
- 396
- 1034
- 506
- 253
- 550
- 814
- 1089
- 495
- 847
- 1232
- 462
- 517
- 462
- 759
- 396
- 308
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