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.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 3.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?
- 4.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 5.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 6.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?
- 7.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 8.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?
- 9.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?
- 10.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?
- 11.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 13.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 14.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 15.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 18.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?
- 19.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?
- 20.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 21.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 22.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 23.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.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?
- 25.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 26.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 27.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 28.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 29.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?
- 30.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 31.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 32.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?
- 33.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 35.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?
- 36.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 37.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?
- 38.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 39.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 40.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 671
- 1001
- 770
- 517
- 671
- 946
- 968
- 847
- 198
- 770
- 924
- 660
- 935
- 858
- 825
- 858
- 847
- 803
- 374
- 583
- 1012
- 737
- 913
- 583
- 748
- 869
- 253
- 594
- 715
- 594
- 1177
- 968
- 418
- 836
- 583
- 847
- 880
- 715
- 429
- 814
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