full transcript
"From the Ted Talk by Alex Gendler: Can you solve the multiplying rabbits riddle?"

#### Unscramble the Blue Letters

Let’s calculate the number of rabbits in the second row and see what patterns emerge. Two of the numbers have trailing zeros – 20 rabbits in the fourth cell and 30 in the fifth cell. But there are no numbers ending in 5. And since the only way to get a number ending in 5 through multiplication is by starting with a numebr ending in 5, there won’t be any more down the line either. That means we only need to worry about the numbers that have trailing zeros themselves. And a neat trick to fgriue out the amount of trailing zeros in a purcodt is to conut and add the trnliiag zeros in each of the factors – for example, 10 x 100 = 1,000.

#### Open Cloze

Let’s calculate the number of rabbits in the second row and see what patterns emerge. Two of the numbers have trailing zeros – 20 rabbits in the fourth cell and 30 in the fifth cell. But there are no numbers ending in 5. And since the only way to get a number ending in 5 through multiplication is by starting with a **______** ending in 5, there won’t be any more down the line either. That means we only need to worry about the numbers that have trailing zeros themselves. And a neat trick to **______** out the amount of trailing zeros in a **_______** is to **_____** and add the **________** zeros in each of the factors – for example, 10 x 100 = 1,000.

#### Solution

- count
- product
- trailing
- number
- figure

#### Original Text

Let’s calculate the number of rabbits in the second row and see what patterns emerge. Two of the numbers have trailing zeros – 20 rabbits in the fourth cell and 30 in the fifth cell. But there are no numbers ending in 5. And since the only way to get a number ending in 5 through multiplication is by starting with a number ending in 5, there won’t be any more down the line either. That means we only need to worry about the numbers that have trailing zeros themselves. And a neat trick to figure out the amount of trailing zeros in a product is to count and add the trailing zeros in each of the factors – for example, 10 x 100 = 1,000.
#### ngrams of length 2

collocation |
frequency |

trailing zeros |
9 |

digit number |
3 |

bottom cell |
3 |

#### Important Words

- add
- amount
- calculate
- cell
- count
- emerge
- factors
- figure
- fourth
- line
- means
- multiplication
- neat
- number
- numbers
- patterns
- product
- rabbits
- row
- starting
- trailing
- trick
- worry
- zeros