Exercise 2.7 - Chapter 2 Numbers Term 3 4th Maths Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

Updated On May 15, 2024

By SaraNextGen

$\mathbf{E x} 2.7$
Simplify the following multiplication facts by adding partial products.
Question 1 .
$9 \times 42$
Answer:
$42=40+2$
$40 \times 9=360$
$2 \times 9=18$
$9 \times 42=360+18=378$

Question $2 .$
$3 \times 78$
Answer:
$78=70+8$
$78 \times 3=210$
$8 \times 3=24$
$3 \times 78=210+24=234$

Question 3 .
$36 \times 12$
Answer:
$\begin{aligned}
&36=30+6 \\
&30 \times 12=360 \\
&6 \times 12=72
\end{aligned}$

Question 4 .
$18 \times 19$
Answer:
$19=10+9$
$10 \times 18=180$
$18 \times 9=162$
$180+162=342$
 

Question $5 .$
$68 \times 31$
Answer:
$68=60+8$
$60 \times 31=1860$
$8 \times 31=248$
$68 \times 31=1860+248=2108$

Question 6 .
$42 \times 21$
Answer:
$42=40+2$
$40 \times 21=840$
$2 \times 21=42$
$42 \times 21=840+42=882$