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 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 2.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?
- 3.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 4.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?
- 5.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 6.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?
- 7.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 8.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 10.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?
- 11.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 12.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 14.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 15.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 16.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 17.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?
- 18.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 20.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 21.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 22.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
- 23.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?
- 24.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 25.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 26.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 27.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 28.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 29.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 31.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?
- 32.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.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?
- 34.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?
- 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?
- 36.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 37.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 38.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 39.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 40.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
Answer key
- 968
- 583
- 726
- 1034
- 1089
- 638
- 1034
- 891
- 968
- 506
- 396
- 484
- 341
- 473
- 418
- 649
- 836
- 1144
- 627
- 308
- 561
- 671
- 759
- 671
- 704
- 517
- 902
- 715
- 561
- 1287
- 649
- 1089
- 539
- 946
- 572
- 594
- 682
- 759
- 374
- 792
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