Question paper, Set 6

(i) Start at $6$ and count on $2$: $2 + 6 = 8$

(ii) Count back $1$ from $6$: $6 - 1 = 5$

Answer: (i) $8$ (ii) $5$

$7$ needs $3$ to make $10$; take $3$ from $7$, which leaves $4$.

$7 + 7 = 10 + 4 = 14$

Answer: $\square = 4$; $7 + 7 = 14$

$\square = 5 - 1 = 4$

Check: $1 + 4 = 5$

Answer: $4$

(i) $80 = 70 + 10$ and $10 - 9 = 1$, so $80 - 9 = 70 + 1 = 71$

(ii) $40 = 30 + 10$ and $10 - 3 = 7$, so $40 - 3 = 30 + 7 = 37$

Answer: (i) $71$ (ii) $37$

Take $4$ from the units digit: $4 - 4 = 0$; the tens digit $4$ stays.

$44 - 4 = 40$

Answer: $40$

1st method: take $3$ out of $6$ first ($6 - 3 = 3$): $13 - 6 = 10 - 3 = 7$

2nd method: add $4$ to both: $13 - 6 = 17 - 10 = 7$

Both methods give $13 - 6 = 7$

Answer: $7$

1st method: take $3$ out of $8$ first ($8 - 3 = 5$): $93 - 8 = 90 - 5 = 85$

2nd method: add $2$ to both: $93 - 8 = 95 - 10 = 85$

3rd method: $93 - 10 = 83$ and $10 - 8 = 2$, so $93 - 8 = 83 + 2 = 85$

All three methods give $93 - 8 = 85$

Answer: $85$

Take $5$ tens from $8$ tens: $8 - 5 = 3$; the units digit $5$ stays.

$85 - 50 = 35$

Answer: $35$

1st method (take the tens first): $82 - 58 = 32 - 8 = 30 - 6 = 24$

2nd method: add $2$ to both: $82 - 58 = 84 - 60 = 24$

3rd method: $82 - 60 = 22$ and $60 - 58 = 2$, so $82 - 58 = 22 + 2 = 24$

4th method (column): $2 < 8$, so borrow $1$ ten: units $12 - 8 = 4$, tens $7 - 5 = 2$

All four methods give $82 - 58 = 24$

Answer: $24$

(i) $170 = 160 + 10$ and $10 - 5 = 5$, so $170 - 5 = 160 + 5 = 165$

(ii) units $9 - 6 = 3$, tens $5 - 1 = 4$, hundreds $4$ stays: $459 - 16 = 443$

Answer: (i) $165$ (ii) $443$

1st method (take the tens first): $470 - 33 = 440 - 3 = 437$

2nd method: add $7$ to both: $470 - 33 = 477 - 40 = 437$

3rd method: $470 - 40 = 430$ and $40 - 33 = 7$, so $470 - 33 = 430 + 7 = 437$

4th method (column): $0 < 3$, so borrow $1$ ten: units $10 - 3 = 7$, tens $6 - 3 = 3$, hundreds $4$

All four methods give $470 - 33 = 437$

Answer: $437$

Take away the tens first: $100 - 10 = 90$

$100 - 11 = 90 - 1 = 89$

Answer: $89$

1st method (column): units $1 < 8$, borrow $1$ ten: $11 - 8 = 3$

tens: $7 < 8$, borrow from the hundred: $17 - 8 = 9$, hundreds $0$

2nd method: take $1$ from both: $181 - 88 = 180 - 87$

take $80$ from both: $= 100 - 7 = 93$

3rd method: $181 - 100 = 81$ and $100 - 88 = 12$, so $181 - 88 = 81 + 12 = 93$

All three methods give $181 - 88 = 93$

Answer: $93$

Add the tens: $20 + 10 = 30$; the units digit $5$ stays.

$20 + 15 = 35$

Answer: $35$

Tens: $60 + 70 = 130$

Units: $5 + 4 = 9$

$65 + 74 = 130 + 9 = 139$

Answer: $139$

$49 \div 9$: $9 \times 5 = 45$, $49 - 45 = 4$

Bring down $8$, we have $48$: $9 \times 5 = 45$, $48 - 45 = 3$

Bring down $6$, we have $36$: $9 \times 4 = 36$, $36 - 36 = 0$

Remainder $0$, so $4986 \div 9 = 554$

Answer: $554$

$7 \div 5$: $5 \times 1 = 5$, $7 - 5 = 2$

Bring down $5$, we have $25$: $5 \times 5 = 25$, $25 - 25 = 0$

Bring down $5$, we have $5$: $5 \times 1 = 5$, $5 - 5 = 0$

Bring down $0$, we have $0$: $0 < 5$, so write $0$ in the quotient

Bring down $2$, we have $2$: $2 < 5$, so write $0$ in the quotient

Bring down $5$, we have $25$: $5 \times 5 = 25$, $25 - 25 = 0$

Bring down $0$, we have $0$: $0 < 5$, so write $0$ in the quotient

Remainder $0$, so $7550250 \div 5 = 1510050$

Answer: $1510050$

$27 \div 9$: $9 \times 3 = 27$, $27 - 27 = 0$

Bring down $4$, we have $4$: $4 < 9$, so write $0$ in the quotient

Bring down $0$, we have $40$: $9 \times 4 = 36$, $40 - 36 = 4$

Bring down $5$, we have $45$: $9 \times 5 = 45$, $45 - 45 = 0$

Remainder $0$, so $27405 \div 9 = 3045$

Do not miss the $0$ in the quotient.

Answer: $3045$

$98 \div 12$: $12 \times 8 = 96$, $98 - 96 = 2$

Bring down $5$, we have $25$: $12 \times 2 = 24$, $25 - 24 = 1$

Bring down $2$, we have $12$: $12 \times 1 = 12$, $12 - 12 = 0$

Remainder $0$, so $9852 \div 12 = 821$

Answer: $821$

$\displaystyle \frac{35}{5}$ means $35 \div 5$.

$5 \times 7 = 35$, so $\displaystyle \frac{35}{5} = 7$

Answer: $7$