Count on and back in constant steps, through zero
What comes next?
25, 17, 9, 1, …
- −8
- 7
- −7
- 9
Show the answer
−7. The numbers go down in 8s, past zero. 1 − 8 = −7.
Huh Lab Maths › Cambridge Primary Maths › Stage 5
Stage 5 of the Cambridge Primary Mathematics (0096) curriculum framework, usually Year 5 (ages 9 to 10). Here is what each part asks, a practice question for each, and the mistakes that cost the most marks.
Each part with one practice question, made by the same engine your child plays.
What comes next?
25, 17, 9, 1, …
−7. The numbers go down in 8s, past zero. 1 − 8 = −7.
△ + □ = 12 and △ − □ = 8.
What number is △?
10. △ is the bigger one. Adding the two facts: △ + △ = 20, so △ = 10 (and □ = 2).
5, 9, 13, 17, …
What is the 10th term?
41. It goes up in 4s. 10th term = 5 + 9 × 4 = 41.
Which of these is a TRIANGULAR number?
10. Triangular numbers make a triangle of dots: 3, 6, 10, 15, 21, 28...
The temperature is 8°C.
It falls by 9°C. What is it now?
−1°C. Count down 9 from 8: you pass 0 and reach −1°C.
Which is equal to 4 × 21?
4 × 20 + 4 × 1. Split 21 into 20 + 1 and multiply each part (the distributive law): 4 × 20 + 4 × 1 = 80 + 4 = 84.
30 − 12 ÷ 3 = ?
26. Divide first: 12 ÷ 3 = 4. Then 30 − 4 = 26.
Which is the best ESTIMATE of 173 × 17?
4 000. Round each number: 173 ≈ 200 and 17 ≈ 20. 200 × 20 = 4 000, so the answer is about 4 000.
10 ÷ 3 = ?
3 r 1. 3 × 3 = 9, and 10 − 9 = 1 left over.
Which of these is a prime number?
5. 5 has exactly two factors: 1 and 5.
Which number is divisible by 8?
728. A number divides by 8 when you can halve it three times and stay whole. 728 ÷ 8 = 91.
What is 7²?
49. 7² means 7 × 7 = 49.
What is the value of the 9 in 5.92?
0.9. The 9 is in the tenths place, so it is worth 9 tenths: 0.9.
0.64 × 1,000 = ?
640. Multiplying by 1,000 moves each digit 3 places to the left.
0.65 × 100 = ?
65. Multiplying by 100 moves each digit 2 places to the left.
3.73 = 3 + ? tenths + 3 hundredths
7. The digit after the point is the tenths: 7.
Round 27.4 to the nearest whole number.
27. 27.4 is between 27 and 28. The tenths digit is 4, so it rounds down to 27.
Which fraction is the same as 2 ÷ 3?
2/3. A fraction IS a division: the top divided by the bottom. 2 ÷ 3 = 2/3.
What is 8/10 of 30?
24. 30 ÷ 10 = 3. Then 3 × 8 = 24.
Write 1 1/2 as an improper fraction.
3/2. 1 wholes are 1 × 2 = 2 2ths. Add the 1: 3/2.
Write 6/10 as a decimal.
0.6. 6 tenths is 0.6.
6/8 + 1/8 = ?
(simplest form)
7/8. Same denominator, so add the tops: 7/8.
1/2 ÷ 2 = ?
1/4. Cutting one 2th into 2 equal pieces makes each piece 2 times smaller: 1/4.
A shape is cut into 5 equal parts and 3 are shaded.
What percentage is shaded?
60%. 3/5 of the shape is shaded. As hundredths: 3/5 = 60/100 = 60%.
Which statement is true?
1.6 < 9.7. Compare the whole numbers first, then the tenths. 9.7 is bigger than 1.6.
3.41 − 1.94 = ?
1.47. Line up the decimal points: 3.41 − 1.94 = 1.47.
3.1 × 2 = ?
6.2. 31 × 2 = 62. One decimal place, so 6.2.
A bag has 2 red and 3 blue counters.
What PROPORTION of the counters are red?
2/5. A proportion compares the part with the WHOLE: 2 red out of 5 counters altogether is 2/5.
A stopwatch shows 10.05 seconds.
How many hundredths of a second is that?
1005. 1 second is 100 hundredths, so 10.05 s is 1005 hundredths.
It is 10:00 in Kuala Lumpur.
Tokyo is 1 hour AHEAD.
What time is it in Tokyo?
11:00. Ahead means later, so add 1 hours: 11:00.
A show starts at 9:40 and ends at 10:35.
How many minutes long is it?
55 min. From 9:40 to 10:35 is 55 minutes.
4.5 hours = ? minutes
270. 4 hours = 240 minutes, and 0.5 of an hour is 30 minutes. 240 + 30 = 270.
How many lines of symmetry does an isosceles triangle have?
1. An equilateral triangle has 3 lines of symmetry, an isosceles triangle has 1 (between its two equal sides), and a scalene triangle has none.
A rectangle is 6 cm by 3 cm.
Which rectangle has the SAME perimeter but a BIGGER area?
5 cm by 4 cm. The perimeter is 2 × (6 + 3) = 18 cm, so the length and the width must still add up to 9. 5 cm by 4 cm does, and its area is 20 cm² against 18 cm². (7 cm by 2 cm keeps the perimeter too, but its area is smaller: the nearer to a square, the more area.)
The questions for this part come with a picture or are played as a game, so they are best tried in Huh Lab.
The questions for this part come with a picture or are played as a game, so they are best tried in Huh Lab.
The questions for this part come with a picture or are played as a game, so they are best tried in Huh Lab.
The questions for this part come with a picture or are played as a game, so they are best tried in Huh Lab.
An angle of 90° is…
right angle. Acute is less than 90°. Obtuse is between 90° and 180°. Reflex is more than 180°.
The questions for this part come with a picture or are played as a game, so they are best tried in Huh Lab.
The questions for this part come with a picture or are played as a game, so they are best tried in Huh Lab.
The questions for this part come with a picture or are played as a game, so they are best tried in Huh Lab.
The questions for this part come with a picture or are played as a game, so they are best tried in Huh Lab.
The questions for this part come with a picture or are played as a game, so they are best tried in Huh Lab.
The questions for this part come with a picture or are played as a game, so they are best tried in Huh Lab.
What is the median?
16, 7, 18, 4, 19
16. Put them in order: 4, 7, 16, 18, 19. The middle one is 16.
The questions for this part come with a picture or are played as a game, so they are best tried in Huh Lab.
You roll a normal dice.
Game A: you LOSE if you roll 5 numbers: 1 to 5.
Game B: you LOSE if you roll a 6.
Which game is riskier?
Game A. Losing in Game A is 5 out of 6, in Game B 1 out of 6. The more likely it is to lose, the riskier the game: Game A.
A bag holds 1 red, 3 blue, 4 green, 6 yellow counters.
One is picked without looking.
Which colour is LEAST likely?
red. There are fewer red counters (1) than any other colour, so red is the least likely.
Huh Lab checks every wrong answer against known mistakes like these, and goes back to the step behind the one your child keeps making.
A reflection goes straight ACROSS the mirror line, never along it.
The image is the same distance from the mirror, on the OTHER side.
Along the corridor, THEN up the stairs: x comes before y.
Estimate first: 672 ÷ 24 is about 700 ÷ 25, so near 28, not 280.
Use a number line: below zero the numbers keep counting, in the other direction.
Quarters plus quarters are still quarters. Only the tops are added.
Perimeter is the fence around it. Area is the grass inside.
Try to make it as a square of dots, then as a triangle: only one of them works.
Short rounds on any topic, a new question every time, the exact mistake found, and a report to you after every session.
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