CRACK THE
DECIMAL CODE.
Decimals are place value with a point in the middle. Read them, compare them, round them, convert them, and operate on them without losing track of the place.
Put every digit in its slot.
Tap a digit in the number to inspect its place and contribution. The point is the boundary between whole-number places and decimal places.
Build the expanded form
Move between decimal and fraction.
Terminating decimals can be written as fractions with powers of 10 in the denominator, then simplified.
Conversion machine
Equalise the places.
Adding zeros to the right of a decimal does not change its value. That makes comparison much easier.
Ordering challenge
Look one place to the right.
To round to a chosen place, inspect the next digit. 5 or more rounds up; 4 or less leaves the chosen digit alone.
Rounding simulator
×10, ×100, ×1000 and divide.
Multiplying by powers of 10 shifts digits to the left in the place-value chart; dividing shifts them to the right.
Calculate with aligned decimal points.
For addition and subtraction, align decimal points. For multiplication, multiply as whole numbers first and restore the total decimal places. For division, make the divisor a whole number by shifting both numbers equally when useful.
Addition
+ 3.7
= 16.18
Subtraction
− 7.86
= 7.34
Multiplication
Division
Explore the number, then predict.
Use the live controls to see how changing place values affects a decimal and its distance from zero.
Fast recall, clean rules.
Flip the cards, say the rule aloud, then reshuffle.
Turn situations into decimal calculations.
Measurements, money, distance and capacity make decimals useful outside the classroom.
Run the chapter like a briefing.
Step through the core ideas in order, or jump to the section you need.
Three attempts. Then reveal.
Every new set creates fresh decimal questions across place value, comparison, rounding and operations.