Grade 6 math worksheet on algebra expressions with variables, asking students to identify the value of x and y.

To solve these problems, we need to substitute the given values for $x$ and $y$ into each expression.

Given:
$x = 4$
$y = 5$

Let's calculate each one step-by-step:

a. $x + 4$
Substitute $x = 4$:
$4 + 4 = 8$

b. $x + 8$
Substitute $x = 4$:
$4 + 8 = 12$

c. $x + 10$
Substitute $x = 4$:
$4 + 10 = 14$

d. $y + 5$
Substitute $y = 5$:
$5 + 5 = 10$

e. $y + 9$
Substitute $y = 5$:
$5 + 9 = 14$

f. $x + 15$
Substitute $x = 4$:
$4 + 15 = 19$

g. $y + 19$
Substitute $y = 5$:
$5 + 19 = 24$

h. $x + y$
Substitute $x = 4$ and $y = 5$:
$4 + 5 = 9$

i. $x + y + 10$
Substitute $x = 4$ and $y = 5$:
$4 + 5 + 10 = 9 + 10 = 19$

j. $x + y + 25$
Substitute $x = 4$ and $y = 5$:
$4 + 5 + 25 = 9 + 25 = 34$

k. $x + y + 100$
Substitute $x = 4$ and $y = 5$:
$4 + 5 + 100 = 9 + 100 = 109$

l. $x + y + 2x$
Substitute $x = 4$ and $y = 5$:
First, calculate $2x$: $2 \times 4 = 8$.
Then add everything up: $4 + 5 + 8$.
$4 + 5 = 9$
$9 + 8 = 17$

m. $x + y - 1$
Substitute $x = 4$ and $y = 5$:
$4 + 5 - 1 = 9 - 1 = 8$

n. $x + y - 4$
Substitute $x = 4$ and $y = 5$:
$4 + 5 - 4 = 9 - 4 = 5$

Final Answer:
a. 8
b. 12
c. 14
d. 10
e. 14
f. 19
g. 24
h. 9
i. 19
j. 34
k. 109
l. 17
m. 8
n. 5