SME
Grade 6 Math · Expressions & Equations
Numerical and algebraic expressions
Use this for “Find the value of 3x + 5 when x = 4.”
Table
Number put in for x (x)
Value of the expression (v)
This is an example. Type your own values to start a new problem.
x
+
=
when
x
=
x
Formulas
v
=
cx
+
k
(value
=
coefficient
×
the
number
for
x
+
constant)
17 = 3 × 4 + 5
Assumptions
•
3x means 3 × x: the coefficient 3 multiplies x. The 5 in 3x + 5 is the constant.
•
A letter stands for a number that can change.
•
Multiply before you add or subtract. The constant can be negative: 2w − 3 adds −3.
Step-by-step
WE KNOW
c = 3 (coefficient), k = 5 (constant), x = 4 (number put in for x)
FIND
value of the expression (v)
Step 1 · Find value of the expression (v)
Use v = cx + k (value = coefficient × the number for x + constant)
Put
4
in
for
x
.
Multiply
before
you
add.
v
=
3
×
4
+
5
v
=
12
+
5
v
=
17
Check
Put the numbers back in. Both sides should match.
17 = 3 × 4 + 5 ✓
Topic check
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