(42-25)+(52-14)............

(42-25)+(52-14)…………

( 42 – 25 ) + ( 52 – 14 ) = 55

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42 – 25 ) + ( 52 – 14 )

17 + ( 52 – 14 )

17 + 38

= 55

$sf(42-25)+(52-14)$

$sf = (42-25)+(52-14)$

$sf = sf17+(52-14)$

$sf = 17 + (52 - 14)$

$sf = 17 + 38$

$sf = 55$