Junior Cycle Maths Ordinary free practice questions with answers

Question 1 (10 marks) [Number and arithmetic]

Suggested maximum time: 5 minutes.

(a) Find the value of 1686 + 988.

(a) Answer: 2674

• Line up the digits by place value: units under units, tens under tens, and so on.
• Add the numbers column by column, starting with the units, carrying when a column adds to 10 or more.
• 1686 + 988 = 2674.

Add and subtract in columns, lining up place values.

(b) Find the value of 2.7 × 5.

(b) Answer: 13.5

• Ignore the decimal point and multiply: 27 × 5 = 135.
• 2.7 has one decimal place, so the answer needs one decimal place: divide by 10.
• 135 ÷ 10 = 13.5, so 2.7 × 5 = 13.5.

To multiply a decimal, multiply as whole numbers, then put the decimal point back in the same position.

(c) Find the value of 10 + 5 × 2.

(c) Answer: 20

• Multiplication comes before addition: 5 × 2 = 10.
• Then add: 10 + 10 = 20.
• So 10 + 5 × 2 = 20.

Order of operations (BIDMAS): brackets, then multiplication and division, then addition and subtraction.

(d) What number is halfway between 15 and 29?

(d) Answer: 22

• The number halfway between two numbers is their mean.
• Add them: 15 + 29 = 44.
• Divide by 2: 44 ÷ 2 = 22.

Halfway between two numbers = (first + second) ÷ 2.

(e) Find the Lowest Common Multiple (LCM) of 3 and 8.

(e) Answer: LCM = 24

• Write the first few multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24.
• Write the first few multiples of 8: 8, 16, 24.
• The smallest number in both lists is 24, so LCM = 24.

The LCM is the smallest number that is a multiple of both numbers: list the multiples of each and find the first match.