Mathematics

Subtracting two-digit numbers

An AR classroom game for Grade 2. Learners can aim with their hands at the camera or play by tapping the screen.

This set has 6 questions in an interactive multiple choice activity.

Curriculum indicatorค 1.1 ป.2/4

Play Host a classroom

A look before you play

Sample questions

A few real prompts from the game to help you choose an activity for your class.

01
45 - 23 = ?
- 22
- 32
- 12
Read the explanation
Ones: five take away three is two. Tens: four take away two is two.
02
78 - 35 = ?
- 33
- 43
- 53
Read the explanation
Eight take away five is three; seven take away three is four.
03
60 - 20 = ?
- 50
- 30
- 40
Read the explanation
Both have zero ones: sixty take away twenty leaves forty.

Before you play

Game teaching guide

What children will practise

Subtract two-digit numbers with and without borrowing, and use subtraction to find money left, as part of solving subtraction number sentences up to 1,000 (indicator ค 1.1 ป.2/4).

What's in the worksheet

6 multiple-choice questions - 45 - 23 = 22 and 78 - 35 = 43 with no borrowing - 60 - 20 = 40 - You have 90 baht and spend 45; 45 is left - 52 - 18 = ? needs borrowing, answer 34 - 100 - 50 = 50

How to use it in class

Use in the first two-digit subtraction lesson, about 6 minutes, solo mode. 52 - 18 is the only borrowing item and makes a bridge to the next lesson. - After 52 - 18, ask "How is this one different?" so pupils notice 2 take away 8 cannot be done - For 90 - 45, check by adding back: 45 + 45 - Play it linked to the class to record results in the mark book

Common sticking points

- Choosing 44 for 52 - 18 by borrowing but not reducing the tens (12 - 8 = 4, then 5 - 1 = 4). Always cross out the 5 and write 4 - Choosing 36 for 52 - 18, only 2 away, from a slip in the ones after borrowing. Check by adding back: 34 + 18 = 52 - Choosing 55 or 35 for 90 - 45 from a slip subtracting from zero. Count on from 45 to 90