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Decimals

Add, subtract, multiply, divide, rounding · Foundations · 24 problems, easy to harder

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How we do it

  1. Times and divide
  2. Plus and minus

The steps for Calculate 0.6 × 0.5 + 1.25. Every solution names its steps, so you always know what comes next.

Worked examples

Calculate 0.4 + 1.25 Easy

The question

Question: work out 0.4 + 1.25.

0.4 + 1.25

1 Add

Line up the decimal points.

We fill the gap with a 0.

A 0 at the end does not change the number.

0.4 plus 1.25 is 1.65.

= 1.65

So the answer is 1.65.

Answer
= 1.65

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Calculate 5 - 2.36 Medium

The question

Question: work out 5 − 2.36.

5 − 2.36

1 Take away

Line up the decimal points.

We fill the gap with a 0.

A 0 at the end does not change the number.

5 minus 2.36 is 2.64.

= 2.64

So the answer is 2.64.

Answer
= 2.64

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Calculate 0.6 × 0.5 + 1.25 Harder

The question

Question: work out 0.6 × 0.5 + 1.25.

0.6 × 0.5 + 1.25

1 Times and divide

Times comes before plus.

Order: ( ) → x² √ → × ÷ → + −
6 × 5 = 30
1 + 1 = 2 digits after the point → 0.30

Forget the points: 6 times 5 is 30.

Together, the numbers have 1 + 1 = 2 digits after the point.

So the answer has 2 too: 0.30, which is 0.3.

= 0.3 + 1.25

2 Plus and minus

Line up the decimal points.

We fill the gap with a 0.

A 0 at the end does not change the number.

0.3 plus 1.25 is 1.55.

= 1.55

So the answer is 1.55.

Let's look back.

First: times and divide.

Last: plus and minus.

Answer
= 1.55

▶ Watch it solved

Practice

Try each one, then open the answer. Stuck? Open the problem to watch every step.

Easy

  1. 0.4 + 1.25
    Answer
    = 1.65
  2. 3.6 - 1.4
    Answer
    = 2.2
  3. 2.75 + 0.5
    Answer
    = 3.25
  4. 0.3 × 0.2
    Answer
    = 0.06
  5. 1.5 × 4
    Answer
    = 6
  6. 4.8 ÷ 0.6
    Answer
    = 8
  7. round 347 to the nearest 10
    Answer
    = 347 ≈ 350
  8. round 3.462 to the nearest tenth
    Answer
    = 3.462 ≈ 3.5
  9. round 5.08 to the nearest whole number
    Answer
    = 5.08 ≈ 5
  10. round 1,250 to the nearest hundred
    Answer
    = 1,250 ≈ 1,300

Medium

  1. 5 - 2.36
    Answer
    = 2.64
  2. 1.2 × 0.35
    Answer
    = 0.42
  3. 0.9 ÷ 0.03
    Answer
    = 30
  4. 7.2 ÷ 0.8 - 1.5
    Answer
    = 7.5
  5. 3.4 - 5.1
    Answer
    = −1.7
  6. round 2.96 to the nearest tenth
    Answer
    = 2.96 ≈ 3.0
  7. round 0.4567 to the nearest hundredth
    Answer
    = 0.4567 ≈ 0.46
  8. round 18,499 to the nearest thousand
    Answer
    = 18,499 ≈ 18,000
  9. round 9.95 to the nearest tenth
    Answer
    = 9.95 ≈ 10.0
  10. 2.5 - 2.5
    Answer
    = 0

Harder

  1. 0.6 × 0.5 + 1.25
    Answer
    = 1.55
  2. (4.2 - 1.7) ÷ 0.5
    Answer
    = 5
  3. round 0.083 to the nearest hundredth
    Answer
    = 0.083 ≈ 0.08
  4. 1.08 ÷ 0.12 × 0.3
    Answer
    = 2.7