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.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?
- 2.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?
- 3.A leapfrog list starts 8, 9 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 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 6.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.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?
- 8.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?
- 9.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 10.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?
- 11.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 12.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 13.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 14.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 16.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 17.A leapfrog list starts 6, 5 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): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 19.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 21.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 22.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 23.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 24.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 25.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?
- 26.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 27.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 30.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 31.A leapfrog list starts 2, 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 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 34.A leapfrog list starts 8, 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): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 36.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 37.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 38.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?
- 39.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 40.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
Answer key
- 583
- 319
- 1232
- 825
- 286
- 539
- 462
- 253
- 682
- 319
- 253
- 715
- 891
- 737
- 759
- 1067
- 770
- 517
- 198
- 1056
- 363
- 627
- 880
- 858
- 506
- 407
- 418
- 1287
- 902
- 968
- 374
- 1144
- 748
- 1056
- 418
- 506
- 1199
- 957
- 451
- 935
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