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 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 2.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 3.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?
- 4.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 6.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 7.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?
- 8.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
- 9.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 12.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 15.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 18.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?
- 19.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?
- 20.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 22.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 23.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 24.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?
- 25.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 27.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 28.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 30.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?
- 31.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?
- 32.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 33.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?
- 34.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 35.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 36.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 37.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 38.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 39.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 40.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
Answer key
- 759
- 550
- 748
- 715
- 319
- 814
- 1111
- 429
- 847
- 319
- 407
- 583
- 1111
- 1023
- 561
- 198
- 704
- 858
- 1012
- 704
- 979
- 605
- 715
- 957
- 968
- 1067
- 495
- 638
- 539
- 759
- 231
- 682
- 308
- 1232
- 253
- 891
- 1144
- 869
- 583
- 847
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