Find using distributive property:
(a)`728xx101`
(b)`5437xx1001`
(c)`824xx25`
(d)`4275xx125`
(e)`504xx35`

Explanation

We will be using the distributive property to solve this.
According to the distributive property,
`a xx (b + c) = a xx b + a xx c`

(a) `728 xx 101`

`101` can be written as `100 + 1728 xx 101`

= `728 xx (100 + 1)`

= `728 xx 100 + 728 xx 1` [using distrbutive property]
= `72800 + 728`

= `73528`
(b) `5437 xx 1001`
`1001` can be written as `1000 +1`
= `5437 xx (1000 + 1)`

= `5437 xx 1000 + 5437 xx 1`
[using distrbutive property]
= `5437000 + 5437`
= `5442437`
(c) `824 xx 25`
= `824 xx (20 + 5)`
= `(824 xx 20) + (824 xx 5)` [using distrbutive property]
= `16480 + 4120`
= `20600`

(d) `4275 xx 125`

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