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
- 1.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 2.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?
- 3.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 4.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 5.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 7.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 8.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 9.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 10.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 11.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?
- 12.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?
- 13.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 15.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 16.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 17.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?
- 18.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?
- 19.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 20.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?
- 21.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?
- 22.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 23.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 24.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?
- 25.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?
- 26.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 27.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?
- 28.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 29.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 30.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 31.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 32.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 33.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 34.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 35.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?
- 36.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 37.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 38.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 39.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 40.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 946
- 462
- 396
- 594
- 429
- 539
- 792
- 616
- 671
- 649
- 286
- 649
- 418
- 781
- 968
- 308
- 616
- 715
- 682
- 396
- 319
- 605
- 869
- 638
- 539
- 1067
- 594
- 462
- 231
- 1089
- 847
- 726
- 473
- 506
- 572
- 935
- 638
- 1122
- 583
- 341
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