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
- 1.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 2.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 3.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 6.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?
- 7.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 8.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 10.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 11.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?
- 12.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?
- 13.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 14.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 15.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 16.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?
- 17.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 18.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?
- 19.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?
- 20.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?
- 21.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 22.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.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?
- 24.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?
- 25.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?
- 26.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?
- 27.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 28.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?
- 29.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?
- 30.A leapfrog list starts 4, 8 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 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 33.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?
- 34.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?
- 35.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 36.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 37.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?
- 38.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 39.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 40.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
Answer key
- 880
- 803
- 1199
- 253
- 143
- 319
- 935
- 946
- 693
- 638
- 1111
- 319
- 715
- 1177
- 825
- 627
- 253
- 429
- 847
- 539
- 1122
- 671
- 638
- 825
- 396
- 781
- 946
- 671
- 693
- 924
- 506
- 1001
- 594
- 429
- 770
- 462
- 1089
- 968
- 308
- 638
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