A number as a product of primes

Difficulty Stretch · Set p7owyy

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1
Write 147 as a product of prime numbers, smallest first, separated by ×.
2
Write 381 as a product of prime numbers, smallest first, separated by ×.
3
Write 54 as a product of prime numbers, smallest first, separated by ×.
4
Write 351 as a product of prime numbers, smallest first, separated by ×.
5
Write 58 as a product of prime numbers, smallest first, separated by ×.
6
Write 329 as a product of prime numbers, smallest first, separated by ×.
7
Write 325 as a product of prime numbers, smallest first, separated by ×.
8
Write 204 as a product of prime numbers, smallest first, separated by ×.
9
Write 135 as a product of prime numbers, smallest first, separated by ×.
10
Write 93 as a product of prime numbers, smallest first, separated by ×.
11
Write 30 as a product of prime numbers, smallest first, separated by ×.
12
Write 262 as a product of prime numbers, smallest first, separated by ×.
13
Write 168 as a product of prime numbers, smallest first, separated by ×.
14
Write 108 as a product of prime numbers, smallest first, separated by ×.
15
Write 108 as a product of prime numbers, smallest first, separated by ×.
16
Write 298 as a product of prime numbers, smallest first, separated by ×.
17
Write 27 as a product of prime numbers, smallest first, separated by ×.
18
Write 297 as a product of prime numbers, smallest first, separated by ×.
19
Write 290 as a product of prime numbers, smallest first, separated by ×.
20
Write 171 as a product of prime numbers, smallest first, separated by ×.

What is in this set

The numbers in this set run from 14 to 400.
93% of them use more than one prime.
A careful solution takes 3 written steps on average.
The mistake this set invites most often, in 44% of the problems: a prime that divides more than once has to appear more than once in the product.
Answers are a short answer exactly as the problem asks for it.

Drawing 240 problems from this page produced 161 different ones, 67% — so a sheet of 20 is a new sheet almost every time.

The same skill, harder or easier

We would put this in front of a grade 6 class. That is our judgement, not a standard, and it is printed here so you can disagree with it. Everything else we put in that year.