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
- 1.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 2.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 3.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?
- 4.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 5.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?
- 6.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 8.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 9.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?
- 10.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?
- 11.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 12.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 13.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?
- 14.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 15.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 16.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 17.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?
- 18.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?
- 19.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?
- 20.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 21.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 22.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
- 23.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 24.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?
- 25.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 26.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?
- 27.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 30.A leapfrog list starts 5, 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 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 33.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 34.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?
- 35.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?
- 36.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?
- 37.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?
- 38.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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
- 583
- 528
- 957
- 902
- 341
- 880
- 946
- 682
- 1287
- 374
- 253
- 869
- 693
- 363
- 198
- 341
- 781
- 495
- 231
- 1111
- 484
- 1232
- 528
- 946
- 1287
- 418
- 462
- 715
- 341
- 979
- 1067
- 286
- 407
- 396
- 759
- 957
- 1111
- 1287
- 803
- 638
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