💯 Percent means per hundred

Percent (%) means “out of 100”. Some percentages are easy to remember: 50% is a half, 25% is a quarter and 10% is a tenth.

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🎯 Rounding

To round, look at the digit to the right of the place you are rounding to. If it is 5 or more, round up. If it is 4 or less, round down.

🪜 The steps

Work from left to right: Divide, Multiply, Subtract, Bring down. Repeat until no digits are left. What remains at the end is the remainder.

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🧩 Remainders and checking

If a number does not divide exactly, the leftover is the remainder. Check any division by multiplying: answer × divisor + remainder = starting number.

📝 Read, plan, solve, check

First read and find the question. Then plan which operations to use and in what order. Solve one step at a time and finally check the answer.

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🔑 Key words

Words give clues: altogether, total mean add; left, difference mean subtract; each, groups of mean multiply; shared equally means divide.

📐 Types of angle

A right angle is exactly 90°. An acute angle is less than 90°. An obtuse angle is between 90° and 180°. A straight angle is 180°.

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📏 Using a protractor

Place the centre mark of the protractor on the point where the two arms meet (the vertex). Line up one arm with the 0° line and read where the other arm crosses the scale.

📈 Parts of a line graph

Every line graph has a title, two axes with labels and a scale. Time usually goes along the bottom (horizontal) axis. Points are joined by a line to show the trend.

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🔍 Reading values and trends

To read a value, go up from the time on the bottom axis to the point, then across to the scale. To find a change, subtract the smaller reading from the larger one.

🍰 Parts of a whole

A fraction is part of a whole. The denominator (bottom) tells how many equal parts there are. The numerator (top) tells how many parts you have.

🍪 A fraction of a number

To find a fraction of a number, divide by the bottom, then multiply by the top.

🚶 Perimeter

Perimeter is the distance all the way around a shape. Add up all the sides.

🟩 Area

Area is the space inside a shape, measured in square units. For a rectangle, area = length × width.

🕰️ Time

There are 60 minutes in an hour and 24 hours in a day. A 24-hour clock keeps counting after noon. To find how long something takes, count on in steps.

🔷 2D shapes

A polygon is a flat shape with straight sides. A regular polygon has equal sides and equal angles. A shape has a line of symmetry if one half folds exactly on to the other.

📏 Units to know

Length is measured in millimetres (mm), centimetres (cm), metres (m) and kilometres (km). Mass (how heavy) is measured in grams (g) and kilograms (kg). Capacity (how much a container holds) is measured in millilitres (ml) and litres (l).

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🔎 Reading scales

Before reading a scale, work out what each small mark is worth: divide the gap between two numbers by the number of spaces. Then count the marks from the last number.

📊 Pictograms and bar charts

A pictogram uses symbols. The key tells you what one symbol is worth, and half a symbol is worth half as much. A bar chart uses bars against a scale that starts at zero and goes up in equal steps.

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🔵 Venn and Carroll diagrams

A Venn diagram sorts things into circles. Things that belong to both groups go in the overlap; things in neither go outside. A Carroll diagram is a table that sorts by two yes-or-no questions, so every item goes in exactly one box.

🌡️ Below zero

Negative numbers are less than zero, such as −3 (“negative three”). On a number line they sit to the left of zero. The further left, the smaller the number: −8 is colder than −3. To add, count right; to subtract, count left, going through zero.

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📍 Coordinates

A coordinate such as (4, 1) gives a position on a grid. The first number tells you how far across; the second tells you how far up. Start from the origin, the corner where the axes meet at (0, 0).