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): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 2.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 3.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 4.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 5.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?
- 6.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 7.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 8.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?
- 9.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 10.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 11.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 12.A leapfrog list starts 4, 7 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, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.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?
- 15.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 18.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?
- 19.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.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?
- 21.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?
- 22.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 23.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 24.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 25.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?
- 26.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 27.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 28.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?
- 29.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?
- 30.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 31.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 33.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 35.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 36.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?
- 37.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?
- 38.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?
- 39.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 40.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
Answer key
- 418
- 462
- 946
- 561
- 682
- 451
- 979
- 671
- 957
- 627
- 671
- 836
- 583
- 913
- 1023
- 704
- 1056
- 1111
- 583
- 671
- 1199
- 396
- 1144
- 1089
- 594
- 1144
- 407
- 1089
- 308
- 726
- 1034
- 869
- 858
- 1199
- 528
- 715
- 825
- 198
- 583
- 660
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