forming an equation

Question

when a ship was sinking, some sailors threw a valuable treasure chest overboard. The deck of the ship was 46 ft above the water's surface. The chest sank to a depth o f387 feet (-387). write an solve a subtraction equation to find the difference between the two locations.

Answer 1

The difference between the two locations will be the original location (the deck of the ship) minus the final location (the bottom of the ocean).  So . . .

 

difference = ship - bottom = 46 ft - (-387 ft)

 

If you need to write this with all symbols, choose a letter for each value, say "s" for ship deck, "b" for ocean bottom and "d" for the difference.  Then,

 

d = s - b = 46 ft - (-387 ft) = 46 ft + (+387 ft) = 46 ft + 387 ft = 433 ft

 

The tricky part is remembering that when you subtract a negative number, there are two minus/negative signs next to each other.  You can turn both of them into + signs.

Answer 2

46ft + 387ft or it can be written 46ft -  -387ft (the minus sign and the negative sign will form a positive or plus) and the answer would be 433 because there is 433 feet between the two points.

Answer 3

x = 46 - (-387)

x = 46 + 387

x = 433

 

Answer 4

The deck of the ship was 46 ft above the water's surface. The chest sank to a depth o f387 feet (-387)

 

The treasure chest starts 46 feet above water (I wish I could draw this).  So, before it drops 387 feet, it first has to drop 46 feet.  Therefore:

 

    46 - (-387)

 

demonstrates the difference betwwen the 2 points.