Multiplication and Division of Signed Mumbers: Complete the missing number

Fill in the missing number:

$10\cdot?=-100$

Let's remember the law:

$(-x)\times(+x)=-x$

Let's think about which number we need to multiply by 10 to get 100:

$10\times10=100$

Now let's put the numbers together with the appropriate sign as written in the law above, and we'll get:

$+10\times(-10)=-100$

$-10$

Fill in the missing number:

$(-6)\cdot?=-12$

Let's remember the law:

$(-x)\times(+x)=-x$

Let's think about which number we need to multiply by 6 to get 12:

$6\times2=12$

Now let's put the numbers together with the appropriate sign as written in the law above, and we'll get:

$-6\times(+2)=-12$

$2$

Fill in the missing number:

$2\cdot?=-8$

Let's remember the law:

$(-x)\times(+x)=-x$

Let's think about which number we need to multiply by 2 to get 8:

$2\times4=8$

Now let's put the numbers together with the appropriate sign as written in the law above, and we'll get:

$+2\times(-4)=-8$

$-4$

Fill in the missing number:

$(-2)\cdot?=-4$

Let's remember the law:

$(-x)\times(+x)=-x$

Let's think about which number we need to multiply by 2 to get 4:

$2\times2=4$

Now let's put the numbers together with the appropriate sign as written in the law above, and we'll get:

$-2\times(+2)=-4$

$2$

Fill in the missing number:

$(-3)\cdot?=-9$

Let's remember the law:

$(-x)\times(+x)=-x$

Let's think about which number we need to multiply by 3 to get 9:

$3\times3=9$

Now let's put the numbers together with the appropriate sign as written in the law above, and we'll get:

$-3\times(+3)=-9$

$3$

Fill in the missing number:

$(-3)\cdot⬜=-15$

Let's remember the rule:

$(-x)\times(+x)=-x$

Let's think about what number we need to multiply by 3 to get 15:

$3\times5=15$

Now let's put the numbers together with the appropriate sign as written in the rule above, and we get:

$-3\times(+5)=-15$

$5$

Fill in the missing number:

$12\cdot?=24$

Let's remember the law:

$(+x)\times(+x)=+x$

Let's think about which number we need to multiply by 12 to get 24:

$2\times2=4$

Now let's put the numbers together with the appropriate sign as written in the law above, and we'll get:

$+12\times+2=24$

$2$

Fill in the missing number:

$7\cdot?=-21$

Let's remember the law:

$(-x)\times(+x)=-x$

Let's think about which number we need to multiply by 7 to get 21:

$7\times3=21$

Now let's put the numbers together with the appropriate sign as written in the law above, and we'll get:

$+7\times(-3)=-21$

$-3$