Mental or Written?

Achievement Objectives
NA4-2: Understand addition and subtraction of fractions, decimals, and integers.
AO elaboration and other teaching resources
NA3-1: Use a range of additive and simple multiplicative strategies with whole numbers, fractions, decimals, and percentages.
AO elaboration and other teaching resources
Specific Learning Outcomes

Carry out column addition and subtraction for whole numbers and decimals.

Solve addition and subtraction problems using decomposition, leading to a written algorithm.

Description of Mathematics

Number Framework Stage 7

Required Resource Materials
Mental or working form (Material Master 5-13)
Activity

Using Number Properties

Problem:
"Which is the better way to solve these problems – mentally or using the standard written forms? 997 + 1 234 4 546 – 2 788.”

Discuss why 997 + 1 234 is easy to solve mentally, using strategies such as, 1 000 + 1234 = 2 234, 2 234 – 3 = 2 231.

Doing 4 546 – 2 788 mentally will be beyond most students, so the standard written form is needed for this one.

Examples: A mixture of addition and subtraction problems (Material Master 5–13).

 

 

 

 

 

 

 

 

Printed from https://nzmaths.co.nz/resource/mental-or-written at 5:15pm on the 29th April 2024