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
- 1.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 2.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 3.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?
- 4.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?
- 5.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 6.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?
- 7.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 8.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?
- 9.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 10.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?
- 11.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 12.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 13.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 14.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 15.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 18.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 19.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?
- 20.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 22.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 23.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?
- 24.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 25.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 26.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 27.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 28.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 29.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 30.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 31.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?
- 32.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?
- 33.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 34.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 36.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 38.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 40.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?
Answer key
- 495
- 1122
- 1089
- 539
- 1111
- 891
- 748
- 407
- 429
- 759
- 451
- 891
- 1067
- 715
- 528
- 429
- 770
- 759
- 957
- 1012
- 473
- 649
- 715
- 462
- 451
- 363
- 836
- 671
- 781
- 869
- 880
- 583
- 946
- 693
- 979
- 473
- 506
- 286
- 803
- 1199
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