The subtrahend is the number to be subtracted. It is the second number in a subtraction.

Being efficient means finding a way to solve a problem quickly whilst also maintaining accuracy.

Solve problems explaining which strategy is most efficient

Maths

Rounding 7-digit numbers to the nearest million

Rounding seven-digit numbers to any power of 10

Solving calculations efficiently

Explore mental and written strategies to solve problems

In this unit pupils will use their knowledge of the composition of 7-digit numbers to solve problems adding and subtracting numbers whilst crossing the millions boundary They will round  7-digit numbers to the nearest million and nearest hundred thousand and solve addition and subtraction problems. In the future unit pupils round to any number of decimal places and learn about significant figures.

In the prior unit pupils estimated the value and position of numbers, including negative numbers, on unmarked or partially marked number lines and calculated intervals across 0. In this unit pupils will use their knowledge of the composition of seven-digit numbers to solve problems, adding and subtracting numbers whilst crossing the millions boundary.

In this unit pupils will use their knowledge of the composition of seven-digit numbers to round them and to solve problems, adding and subtracting numbers whilst crossing the millions boundary.

Rounding and solving problems with numbers up to 7 digits

constant difference then column subtraction

Match these expressions to the strategy you would use to calculate them.

A charity needs to raise £200,000 and it has already raised £57,306 Which strategy is most efficient to use to calculate how much more money it needs to raise?

A charity raises £246,803 in a fundraising event. It then raises another £1,907,368   Which strategy is most efficient to use to calculate how much money it has raised in total?

Find the missing number in this equation.
508,914 = {{ }}  + 205,730

Calculate the multi-step equation. Think about the strategy which will be most efficient.
205,677 + 499,998 − 200,000 = {{ }}

Two numbers have a total of 1,690,768 and a difference of 999,412
What are the two numbers? 345,678 and {{ }}

Use an efficient method to find the sum of 14,875 and 3,123

Use an efficient method to find the sum of 9,308 and 5,245

Match the expression to the correct difference.

Use a number line to calculate 50,000 − 34,995 = {{ }}

Use the ‘constant difference’ strategy to calculate 15,000 − 2,375 = {{ }}

Two numbers have a total of 367,200 If one of the numbers is 320,000 what is the other number?

Solve problems explaining which strategy is most efficient

Lesson outcome