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
- 1.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 2.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 3.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
- 4.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 5.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?
- 6.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 7.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?
- 8.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 9.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 10.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?
- 11.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 13.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 14.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?
- 15.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 16.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?
- 17.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 18.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 19.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 20.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.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?
- 22.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?
- 23.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 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 4, 3 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 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.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?
- 28.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?
- 29.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?
- 30.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?
- 31.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 32.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?
- 33.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 34.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?
- 35.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?
- 36.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.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?
- 39.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 40.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
Answer key
- 253
- 1122
- 1012
- 473
- 198
- 858
- 1199
- 1056
- 825
- 957
- 847
- 715
- 1199
- 319
- 968
- 506
- 308
- 363
- 1232
- 902
- 781
- 1089
- 143
- 858
- 484
- 407
- 462
- 891
- 1144
- 649
- 462
- 1232
- 814
- 847
- 671
- 308
- 759
- 418
- 682
- 913
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