

Cathy
and Ahmed are trying to figure out the number of counters that will balance the lamps on the
scale. Cathy knows that 12 counters weigh more than the 3 lamps. Ahmed suggested balancing the
scale by adding 3 counters to the right side of the scale, along with the 3
lamps.
Order the steps they use to solve the
equation.
a.  Ahmed made sure there was only one equal sign in each
step.  b.  Cathy and Ahmed checked the solution be subtituting the answer
for the variable to make the equation true. 3(3) + 3 = 12.  c.  Cathy wrote the
balance problem as an algebraic equation using the variable l. l represents the number
of counters that equal the weight of each lamp. 3l + 3 = 12.  d.  Cathy and Ahmed
solved for the variable l. 3l = 9, l = 3.  e.  Ahmed took away
3 counters from each side, and both sides balanced. 3l + 3  3 = 12 
3.   



Jay
wants to find the number of counters that will balance the lamps on the scale. He knows that 21
counters weigh more than the 4 lamps. He adds 1 counter along with the 4 lamps to balance the
scale.
Order the steps he takes to solve the
equation.
a.  Jay solves for the variable x. 4x = 20, so
x = 5.  b.  Jay writes the problem as an algebraic equation using the
variable x. 4x + 1 = 21.  c.  He substitutes the answer for the variable to check the
equation was true. 4(5) + 1 = 21.  d.  He makes sure there was only 1 equal sign in each
step.  e.  He takes away 1 counter from each side, both sides still
balance. 4x + 11 = 211.   
