BIDMAS
The Maths Habit
Sam gets dressed. Which order works?
A
1Shoes
→2Socks
The socks will not go on.B1Socks
→2Shoes
✓ This order works.
Ali and Bea work out the same calculation.
6 + 4 × 3
Ali gets30
Bea gets18
Who is right? Bea. × goes first.
- Operation
- Something you do to numbers. It is a job in a calculation.
- Brackets
- Two curved lines round part of a calculation.
- BIDMAS
- The order to do the jobs in a calculation.
+−×÷
( )
+ ×
first job=answer 1
+ answer 1=answer
- 1Ring the first job.The higher step goes first: × or ÷.
- 2Work it out.Write it in the boxes.
- 3Do the last job.Use your answer from step 2.
Which job is first?
1Ring the first job.2Work it out.3Do the last job.
3 + 4 × 2Multiply
10 − 6 ÷ 2Divide
5 × 2 + 1Multiply
Work out
1Ring the first job.
3 + 4 × 5
2Work it out.
4×5=20
3Do the last job.
3+20=23
Work out
1Ring the first job.
20 − 3 × 5
2Work it out.
3×5=15
3Do the last job.
20−15=5
Work out
1Ring the first job.
3 + 4 × 5
2Work it out.
4×5=20
3Do the last job.
3+20=23
1Ring the first job.2Work it out.3Do the last job.
Work out
1Ring the first job.
6 + 3 × 10
2Work it out.
3×10=30
3Do the last job.
6+30=36
Work out
1Ring the first job.
3 + 4 × 5
2Work it out.
4×5=20
3Do the last job.
3+20=23
1Ring the first job.2Work it out.3Do the last job.
Work out
1Ring the first job.
12 − 8 ÷ 2
2Work it out.
8÷2=4
3Do the last job.
12−4=8
Work out
1Ring the first job.
3 + 4 × 5
2Work it out.
4×5=20
3Do the last job.
3+20=23
1Ring the first job.2Work it out.3Do the last job.
Work out
1Ring the first job.
5 × 4 + 7
2Work it out.
5×4=20
3Do the last job.
20+7=27
1Ring the first job.2Work it out.3Do the last job.
1Ring the first job.
14 + 2 × 3= 102Work it out.
2×3=6
3Do the last job.
4+6=10
1Ring the first job.
215 − 10 ÷ 5= 132Work it out.
10÷5=2
3Do the last job.
15−2=13
1Ring the first job.
33 × 5 − 6= 92Work it out.
3×5=15
3Do the last job.
15−6=9
1Ring the first job.
49 + 20 ÷ 10= 112Work it out.
20÷10=2
3Do the last job.
9+2=11
( + ) ×
first job=answer 1
answer 1 × =answer
- 1Ring the first job.Brackets first. Then × or ÷.
- 2Work it out.Write it in the boxes.
- 3Do the last job.Use your answer from step 2.
Which job is first?
1Ring the first job.2Work it out.3Do the last job.
(2 + 3) × 4Brackets
2 + 3 × 4Multiply
10 − (4 + 1)Brackets
Work out
1Ring the first job.
(2 + 3) × 4
2Work it out.
2+3=5
3Do the last job.
5×4=20
Work out
1Ring the first job.
(10 − 4) × 2
2Work it out.
10−4=6
3Do the last job.
6×2=12
Work out
1Ring the first job.
(2 + 3) × 4
2Work it out.
2+3=5
3Do the last job.
5×4=20
1Ring the first job.2Work it out.3Do the last job.
Work out
1Ring the first job.
5 × (1 + 3)
2Work it out.
1+3=4
3Do the last job.
5×4=20
Work out
1Ring the first job.
(2 + 3) × 4
2Work it out.
2+3=5
3Do the last job.
5×4=20
1Ring the first job.2Work it out.3Do the last job.
Work out
1Ring the first job.
(9 + 6) ÷ 5
2Work it out.
9+6=15
3Do the last job.
15÷5=3
Work out
1Ring the first job.
(2 + 3) × 4
2Work it out.
2+3=5
3Do the last job.
5×4=20
1Ring the first job.2Work it out.3Do the last job.
Work out
1Ring the first job.
18 − (2 + 7)
2Work it out.
2+7=9
3Do the last job.
18−9=9
Answer sheet
Is it right?
Thumbs up: right. Thumbs down: wrong.
2 + 3 × 4 = 20
Wrong: it is 14(2 + 3) × 4 = 20
Right10 − 2 × 3 = 4
Right6 + 6 ÷ 2 = 6
Wrong: it is 9(8 − 3) × 2 = 10
Right
Work out 2 + 32. (32 means 3 × 3.)
11Work out 10 − 4 + 3. (+ and − are on the same step: go from left to right.)
9Put one pair of brackets into 4 + 6 × 2 − 1 so that the answer is 19.
(4 + 6) × 2 − 1
Work out 4 + 3 × 5
19Work out (8 − 2) × 3
18Work out 20 − 6 ÷ 2
17