Addition Practice Calculator

Work out addition practice instantly with clear inputs, formula shown and shareable results.

About Addition Practice Calculator

The correct sum is the two numbers added, and the marking compares it against the answer the child gave so the size and direction of the slip is visible. Most addition errors are carry errors, so knowing whether a units-column carry was required tells you exactly which step to re-teach.

Formulas

Sum

Sum = first number + second number

Marking

Error = answer given - correct sum; a carry is needed when units(a) + units(b) >= 10

Worked example

With the default values below, Addition Practice Calculator returns Correct sum of 75.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

First number: 27
Second number: 48
Answer given: 65

Results

Correct sum: 75.00
Marking: Too low by 10
Difference from the answer given: -10.00
Carry needed in the units column: 1

Step by step

1Values used
2Sum
3Marking
4Correct sum= 75.00
5Marking= Too low by 10
6Difference from the answer given= -10.00
7Carry needed in the units column= 1

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Addition Practice figure worked out?

Sum = first number + second number. The correct sum is the two numbers added, and the marking compares it against the answer the child gave so the size and direction of the slip is visible.

Why does this matter?

Most addition errors are carry errors, so knowing whether a units-column carry was required tells you exactly which step to re-teach.

What do I need to enter?

Enter first number, second number, answer given. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.