Sam received 87 dollars for his birthday. He went to a sporting goods store and bought a baseball glove, baseball, and bat. He had 10 dollars left over, how much did he spent on the baseball gear?

4 Answers
Aug 8, 2016

#=77$#

Explanation:

#87-10#
#=77$#

Aug 8, 2016

$77

Explanation:

This can be solved by #color(blue)"subtracting"# 10 from 87

That is 87 - 10 = 77

or by #color(blue)"counting on" # from 10 to 87

#10to20=color(red)(10)#
#20to30=color(red)(10)#
#30to40=color(red)(10)#
#40to50=color(red)(10)#
#50to60=color(red)(10)#
#60to70=color(red)(10)#
#70to80=color(red)(10)#

#80to87=color(red)(7)#

Total spent is then

# = color(red)(10+10+10+10+10+10+10+7)=$77#

Aug 8, 2016

He spent $77

Explanation:

Although the calculation is very easy, the purpose of this type of question is to be able to interpret 'word sums' and decide on a correct operation.

We are actually looking for "THE DIFFERENCE" between the amount of money he started with and the amount he had at the end.

#87 - ? = 10#

"DIFFERENCE" means subtract.

#87 -10 = 77#

He spent $77.

Aug 11, 2016

A slightly different way of dealing with subtraction.

#$77#

Explanation:

Received #color(green)($87)#.

But #color(green)($87)# can be written as #color(green)($77+$10)#

After spending some money he had #color(blue)($10" left")#.

#color(red)("So he spent:")#

#color(green)($77+$10)color(blue)( - $10)#

#color(red)(=$77+0" "=" "$77)#