The activities are grouped in the order kids usually need them:
What decimals mean. Tenths and hundredths as pieces of one whole, the link to fractions, and the value of each digit.
Decimals on the number line. Seeing a decimal as one number with a location, including zooming in between two tenths, crossing over a whole number, rounding by asking which side is closer, and estimating with benchmarks like 1/2.
Comparing and ordering. Reasoning by place value, so that "longer means bigger" stops working as a shortcut, and seeing that there is always another decimal in between.
Place value and powers of ten. Naming the same amount in different units (1.8 = 180 hundredths), building numbers from place values with regrouping, telling a digit's place from its value, and why multiplying by 10 shifts every digit one place.
Not sure? Print the Quick check-up. It has 3 problems from every activity, and the answer key has a "What to look for" note for each section. Start practice at the first stage where your child makes mistakes, and move up when it feels easy.
The most common decimal mistakes come from treating the digits after the point as a separate whole number (thinking 0.45 is bigger than 0.5 because 45 is bigger than 5). Many activities are built to catch that on purpose.
Quick start:
Numbers Used by every activity
Decimal places to use
The shaded grids can only show tenths and hundredths. Comparing and ordering work best with at least two choices, so decimals of different lengths can be mixed.
Stage 2 settings Number lines and rounding
Round to the nearest
A number is only rounded to a place it has more digits than, so with tenths selected, rounding is always to the nearest whole number.
With fewer marks, a hundredth like 0.37 goes on a line marked only in tenths, so your child has to picture where it falls between 0.3 and 0.4.
Stage 4 settings Multiplying and dividing by 10, 100, 1,000