Page 54 - Math Smart - 7

Check My
Understanding

O Write an algebraic expression for each question.
a) I have m marbles in a packet. I put another 3 marbles in the packet.
How many marbles are in the packet now?
b) I have m marbles. I lose 7 marbles. How many marbles do I have left?
c) I have 4 packets of marbles. Each packet contains m marbles.
How many marbles do I have altogether?
© A group of 25 school pupils are divided into n groups.
How many pupils are there in each group?

© A pencil costs a cents and a ruler costs b cents.
What is the total cost of
a) 6 pencils,
b) 4 rulers and
c) 6 pencils and 4 rulers in cents?

O Adrian, Cheng and Daylen are playing with some marbles.
Cheng has 4 marbles more than Adrian. Daylen has 5 marbles fewer than Adrian.
If Cheng has x marbles,
a) how many marbles does Adrian have?
b) how many marbles does Daylen have?
O Choose the algebraic expression that matches each part.

a) Take a number and multiply it by 6. Then add another number to that answer.
i) 6x ii) 6x + 6 iii) x + 6 iv) 6% + y v) x + y +

b) Take a number and multiply it by 3. Then subtract another number from that answer.
i) 3^-1 ii) 3p - q iii) 3p - 3 iv) 3p v) p - 3 +
c) Take a number and multiply it by 3. Add another number to that answer, and then
subtract 8.
8
8
i) 3a + 3b — S ii) 3ab - iii) 3a - iv) 3a + 6 - v) a + b -
S
O Decide and assign the unknowns. Then write an algebraic expression for each of the following.
a) Take a number and multiply it by 10. Take another number and multiply it by 6.
Then add the two numbers together.
b) Double the sum of p and 15.
c) Add two numbers together. Multiply it by 15. Then subtract another number
from your answer.
d) Add 1 to half of x.

©* Challenge!
There are x pupils in a class. 22 of them are girls and 15 of them wear spectacles. Write down an
algebraic expression for each situation below.
a) The number of boys in the class.
b) The number of pupils not wearing spectacles in class.

Introduction to Algebra and Equations