Question

this a mom I try to know how to do this math so I can hlep my son I don't get that all. Help on the b section.

Answer 1

Inside the smaller square:

`7\cdot8=56`

On the right edge:

`7\cdot(3)/(4)=(21)/(4)=5(1)/(4)`

On the right corner:

`(4)/(5)\cdot(3)/(4)=(12)/(20)=(3)/(5)`

On the down strip:

`(4)/(5)\cdot8=(32)/(5)=6(2)/(5)`

B)

We now need to add all the partial products. The first part is:

`56+5(1)/(4)+6(2)/(5)+(3)/(5)`

When adding mixed fractions we need to add the "integer" parts and the "fractional" parts. To sum the fractional parts we need to calculate the LCM, which is done by factoring the different denominators, in this case we have two denominators "5" and "4", since they are both prime numbers they only have one factor, which is themselves and we can multiply them directly to find the LCM.

`\begin{gathered} 56+5(5\cdot1)/(20)+6(2\cdot4)/(20)+(3\cdot4)/(20) \\ 56+5(5)/(20)+6(8)/(20)+(12)/(20) \end{gathered}`

We can now sum the integers and numerators:

`67(25)/(20)`

For the last part we need to change the improper fraction by adding one unit to the integer and subtracting 20/20 on the fraction.

`68(5)/(20)`

The fractional part can be simplified by dividing the numerator and denominator by 5.

`68(1)/(4)`