Find Factors and Identify Primes - 4th Grade Math
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Determine whether $97$ is prime or composite.
Determine whether $97$ is prime or composite.
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Prime. $97$ has only factors $1$ and $97$.
Prime. $97$ has only factors $1$ and $97$.
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What is the definition of a factor of a whole number $n$?
What is the definition of a factor of a whole number $n$?
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A whole number that divides $n$ with no remainder. A factor divides evenly into the number.
A whole number that divides $n$ with no remainder. A factor divides evenly into the number.
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Identify all factor pairs of $36$.
Identify all factor pairs of $36$.
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$(1,36)$, $(2,18)$, $(3,12)$, $(4,9)$, $(6,6)$. Find pairs that multiply to $36$.
$(1,36)$, $(2,18)$, $(3,12)$, $(4,9)$, $(6,6)$. Find pairs that multiply to $36$.
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Identify all factor pairs of $56$.
Identify all factor pairs of $56$.
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$(1,56)$, $(2,28)$, $(4,14)$, $(7,8)$. Find pairs that multiply to $56$.
$(1,56)$, $(2,28)$, $(4,14)$, $(7,8)$. Find pairs that multiply to $56$.
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Identify all factor pairs of $63$.
Identify all factor pairs of $63$.
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$(1,63)$, $(3,21)$, $(7,9)$. Find pairs that multiply to $63$.
$(1,63)$, $(3,21)$, $(7,9)$. Find pairs that multiply to $63$.
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Determine whether $72$ is a multiple of $8$.
Determine whether $72$ is a multiple of $8$.
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Yes, because $72 = 8 \times 9$. Check if $8$ divides $72$ evenly.
Yes, because $72 = 8 \times 9$. Check if $8$ divides $72$ evenly.
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Determine whether $70$ is a multiple of $9$.
Determine whether $70$ is a multiple of $9$.
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No, because $70 \div 9$ is not a whole number. $70 \div 9 = 7.\overline{7}$, not a whole number.
No, because $70 \div 9$ is not a whole number. $70 \div 9 = 7.\overline{7}$, not a whole number.
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Determine whether $81$ is a multiple of $3$.
Determine whether $81$ is a multiple of $3$.
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Yes, because $81 = 3 \times 27$. Check if $3$ divides $81$ evenly.
Yes, because $81 = 3 \times 27$. Check if $3$ divides $81$ evenly.
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Determine whether $91$ is a multiple of $7$.
Determine whether $91$ is a multiple of $7$.
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Yes, because $91 = 7 \times 13$. Check if $7$ divides $91$ evenly.
Yes, because $91 = 7 \times 13$. Check if $7$ divides $91$ evenly.
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Identify all factor pairs of $24$.
Identify all factor pairs of $24$.
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$(1,24)$, $(2,12)$, $(3,8)$, $(4,6)$. Find pairs that multiply to $24$.
$(1,24)$, $(2,12)$, $(3,8)$, $(4,6)$. Find pairs that multiply to $24$.
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Which classification is correct for $1$: prime, composite, or neither?
Which classification is correct for $1$: prime, composite, or neither?
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$1$ is neither prime nor composite. By definition, primes and composites must be greater than $1$.
$1$ is neither prime nor composite. By definition, primes and composites must be greater than $1$.
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Identify all factor pairs of $45$.
Identify all factor pairs of $45$.
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$(1,45)$, $(3,15)$, $(5,9)$. Find pairs that multiply to $45$.
$(1,45)$, $(3,15)$, $(5,9)$. Find pairs that multiply to $45$.
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Determine whether $49$ is prime or composite.
Determine whether $49$ is prime or composite.
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Composite. $49 = 7 \times 7$, so it has more than two factors.
Composite. $49 = 7 \times 7$, so it has more than two factors.
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Determine whether $63$ is a multiple of $9$.
Determine whether $63$ is a multiple of $9$.
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Yes, because $63 = 9 \times 7$. Divide $63 \div 9 = 7$, which is a whole number.
Yes, because $63 = 9 \times 7$. Divide $63 \div 9 = 7$, which is a whole number.
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Find all factor pairs of $64$.
Find all factor pairs of $64$.
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$(1,64)$, $(2,32)$, $(4,16)$, $(8,8)$. Powers of $2$: $1 \times 64$, $2 \times 32$, $4 \times 16$, $8 \times 8$.
$(1,64)$, $(2,32)$, $(4,16)$, $(8,8)$. Powers of $2$: $1 \times 64$, $2 \times 32$, $4 \times 16$, $8 \times 8$.
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Determine whether $70$ is a multiple of $8$.
Determine whether $70$ is a multiple of $8$.
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No, because $70$ is not $8 \times$ a whole number. $70 \div 8 = 8.75$, which is not a whole number.
No, because $70$ is not $8 \times$ a whole number. $70 \div 8 = 8.75$, which is not a whole number.
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Determine whether $56$ is a multiple of $7$.
Determine whether $56$ is a multiple of $7$.
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Yes, because $56 = 7 \times 8$. Divide $56 \div 7 = 8$, which is a whole number.
Yes, because $56 = 7 \times 8$. Divide $56 \div 7 = 8$, which is a whole number.
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Which numbers are the factors of $21$?
Which numbers are the factors of $21$?
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$1$, $3$, $7$, $21$. Find all numbers that divide $21$ evenly.
$1$, $3$, $7$, $21$. Find all numbers that divide $21$ evenly.
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Find all factor pairs of $45$.
Find all factor pairs of $45$.
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$(1,45)$, $(3,15)$, $(5,9)$. Check pairs: $1 \times 45$, $3 \times 15$, $5 \times 9$.
$(1,45)$, $(3,15)$, $(5,9)$. Check pairs: $1 \times 45$, $3 \times 15$, $5 \times 9$.
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Find all factor pairs of $36$.
Find all factor pairs of $36$.
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$(1,36)$, $(2,18)$, $(3,12)$, $(4,9)$, $(6,6)$. Check: $1 \times 36$, $2 \times 18$, $3 \times 12$, $4 \times 9$, $6 \times 6$.
$(1,36)$, $(2,18)$, $(3,12)$, $(4,9)$, $(6,6)$. Check: $1 \times 36$, $2 \times 18$, $3 \times 12$, $4 \times 9$, $6 \times 6$.
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