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Hong Kong
Stage 1

Solve problems with mixed operations

Lesson

Sometimes you need more than one step to solve a number problem, so it helps to look at how to work through each step.  Let's see some examples of how you might do this, using written problems to start with.

Worked examples

Question 1

Sally and her mum were at home. Her grandma came around to visit, then her dad and brother came home together.

  1. Which number sentence matches the number of people in the house?

    $2-1+2$21+2

    A

    $2+1-2$2+12

    B

    $2+1+2$2+1+2

    C

    $1+1+2$1+1+2

    D
  2. How many people are in the house altogether?

Question 2

There are $80$80 students at an athletics carnival. They are divided into $10$10 teams.

In the first team, $2$2 students become unwell and cannot participate.

  1. How many players are left in the first team?

Question 3

Charlie has $50$50cm of ribbon, which he cuts into $10$10 equal pieces.

He then selects one of these pieces, and cuts $2$2cm off it.

  1. How long is this piece of ribbon now?

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